System for testing an integrated circuit of a device and its method of use

ABSTRACT

A method of testing an integrated circuit of a device is described. Air is allowed through a fluid line to modify a size of a volume defined between the first and second components of an actuator to move a contactor support structure relative to the apparatus and urge terminals on the contactor support structure against contacts on the device. Air is automatically released from the fluid line through a pressure relief valve when a pressure of the air in the fluid line reaches a predetermined value. The holder is moved relative to the apparatus frame to disengage the terminals from the contacts while maintaining the first and second components of the actuator in a substantially stationary relationship with one another. A connecting arrangement is provided including first and second connecting pieces with complementary interengaging formations that restricts movement of the contactor substrate relative to the distribution board substrate in a tangential direction.

BACKGROUND OF THE INVENTION

1). Field of the Invention

This invention relates to an apparatus that is used for full-wafertesting and/or burn-in testing and/or built-in self-testing.

2). Discussion of Related Art

Microelectronic circuits are usually fabricated in and on semiconductorwafers. Such a wafer is subsequently “singulated” or “diced” intoindividual dies. Such a die is typically mounted to a supportingsubstrate for purposes of providing rigidity thereto and electroniccommunication with an integrated or microelectronic circuit of the die.Final packaging may include encapsulation of the die and the resultingpackage can then be shipped to a customer.

It is required that the die or the package be tested before beingshipped to a customer. Ideally, the die should be tested at an earlystage for the purposes of identifying the defects that occur duringearly stage manufacturing.

The earliest stage that a die can be tested is after completion of themanufacture of circuits at wafer level and before a wafer is singulated.Full-wafer testing carries with it a number of challenges. One challengein full-wafer testing is that there are a large amount of contacts on awafer and that a large number of power, ground, and signal connectionsthus have to be made.

SUMMARY OF THE INVENTION

The invention provides a method of testing an integrated circuit of adevice, including holding the device against a surface of a holder,moving a contactor board assembly relative to the holder to bringterminals of the contactor board assembly into contact with contacts onthe device, and providing signals through the terminals and contacts tothe integrated circuit.

The method may further include allowing air through a fluid line tomodify a size of a volume defined between the first and secondcomponents of the actuator to move the contactor support structurerelative to the apparatus frame.

The method may further include automatically releasing air from thefluid line though a pressure relief valve when a pressure of the air inthe fluid line reaches a predetermined value.

In the method, the device may be a first device, further includingreducing a pressure in the internal volume while maintaining theterminals in contact with the contacts, moving the holder relative tothe apparatus frame to disengage the terminals from the contacts whilemaintaining the first and second components of the actuator in asubstantially stationary relationship with one another, replacing thefirst device with a second device by removing the first device from theholder and holding the second device against the surface of the holder,moving the holder relative to the frame to bring the terminals intocontact with contacts of the second device while the first and secondcomponents of the actuator remain in substantially in the stationaryrelationship relative to one another, increasing the pressure in thevolume to urge the terminals against the contacts on the second device,and providing signals through the terminals and the contacts of thesecond device to an integrated circuit of the second device.

In the method, the first and second portions of the actuator may be acylinder and a piston, respectively, the piston being located in thecylinder so that the cylinder and the piston jointly define the volume,further including modify a pressure of the volume and move the pistonrelative to the cylinder.

The method may further include adjusting the force of at least onespring that connects the piston to the cylinder to level the pistonrelative to the cylinder.

In the method, the actuator may include inflatable and deflatablebladder, the first and second portions of the actuator being opposingsides of the bladder.

In the method, a plurality of electrical components may be mounted onthe contactor board assembly.

In the method, the electrical components may be mounted on a side on thecontactor board assembly opposing the terminals held by the contactorboard assembly.

In the method, the electrical components may be located between a forcedistribution substrate and the contactor board assembly, furtherincluding transferring force from the contactor substrate to the forcedistribution substrate through a stand-off component.

The method may further include locating a compensating piece against afirst piece of a subassembly that may include the contactor boardassembly, the compensating piece having a profiled surface to improveplanarity of a surface of the subassembly other than the profiledsurface of the compensating piece.

In the method, the contactor support structure may include adistribution board substrate and a contactor substrate mounted to thedistribution board substrate.

The method may further include connecting the contactor substrate to thedistribution board substrate with at least a first connectingarrangement, the first connecting arrangement including first and secondconnecting pieces with complementary interengaging formations that allowfor movement of the contactor substrate relative to the distributionboard substrate in a first radial direction and restricts movement ofthe contactor substrate relative to the distribution board substrate ina first tangential direction transverse to the first radial direction.

In the method, the distribution board may have a plurality of layershaving a plurality of different stiffnesses, one of the layers in a halfof the distribution board substrate opposing the terminals held by thecontactor support structure being stiffer than a majority of the layers.

The method may further include removably mounting a cartridge frame of acartridge to the apparatus frame, the contactor board assembly formingpart of the cartridge, and connecting a surface of a connector interfaceto a surface of a contactor interface.

In the method, the cartridge may include a common subassembly and afirst unique contactor subassembly, further including replacing thefirst unique contactor subassembly with a second unique contactorsubassembly.

The method may further include reducing a pressure in an area betweenthe common subassembly and the second unique contactor subassembly.

The invention also provides an apparatus for testing an integratedcircuit of a device, including an apparatus frame, a holder for thedevice, secured to the apparatus frame, a contactor support structureheld by the apparatus frame, a plurality of terminals held by thecontactor support structure, the holder and contactor support structurebeing movable relative to one another so that each one of the terminalsreleasably makes contact with a respective contact of the device, apower source, a power electrical path connecting the power source to apower terminal of the terminals held by the support structure, a signalsource, and a plurality of signal electrical paths, each connecting thesignal source to a respective signal terminal of the terminals held bythe support structure.

The apparatus may further include an actuator connected between theapparatus frame and the contactor support structure, having first andsecond portions that may be movable relative to one another to move thecontactor support structure relative to the apparatus frame and towardthe surface of the holder so that the terminals may be urged againstcontacts of the device.

In the apparatus, the actuator may have a volume defined between thefirst and second components and a fluid line connected to the volume toallow air through the volume and thereby modify a size of the volume andmove the contactor support structure relative to the apparatus frame.

The apparatus may further include a pressure relief valve connected tothe fluid line to automatically release air from the fluid line thoughthe pressure relief valve when a pressure of the air in the fluid linereaches a predetermined value.

In the apparatus, the device may be a first device, further including aprocessor, a memory connected to the processor, and a computer programstored in the memory and executable by the processor to carry out amethod including reducing a pressure in the internal volume whilemaintaining the terminals in contact with the contacts, moving theholder relative to the apparatus frame to disengage the terminals fromthe contacts while maintaining the first and second components of theactuator in a substantially stationary relationship with one another,replacing the first device with a second device by removing the firstdevice from the holder and holding the second device against the surfaceof the holder, moving the holder relative to the frame to bring theterminals into contact with contacts of the second device while thefirst and second components of the actuator remain in substantially inthe stationary relationship relative to one another, increasing thepressure in the volume to urge the terminals against the contacts on thesecond device, and providing signals through the terminals and thecontacts of the second device to an integrated circuit of the seconddevice.

In the apparatus, the first and second portions of the actuator may be acylinder and a piston, respectively, the piston being located in thecylinder so that the cylinder and the piston jointly define a volume,further including, the fluid line being connected to the volume tomodify a pressure of the volume and move the piston relative to thecylinder.

The apparatus may further include a spring, and a spring adjustmentmechanism having a first portion secured to the piston and a secondportion connected to the spring, the spring adjustment mechanism beingadjustable to adjust a force of the spring and level the piston relativeto the cylinder.

In the apparatus, the actuator may include inflatable and deflatablebladder, the first and second portions of the actuator being opposingsides of the bladder.

The apparatus may further include a plurality of electrical componentsmounted on the contactor support structure.

In the apparatus, the electrical components may be mounted on a side onthe contactor support structure opposing the terminals held by thecontactor support structure.

The apparatus may further include a force distribution substrate, theelectrical components being located between the force distributionsubstrate and the force distribution substrate and the contactor supportstructure, and a stand-off component between the force distributionsubstrate and the contactor substrate to transfer force from thecontactor substrate to the force distribution substrate.

The apparatus may further include a subassembly having the contactorsupport structure, the terminals and a compensating piece with aprofiled surface that improves planarity of a surface of the subassemblyother than the profiled surface of the compensating piece.

In the apparatus, the contactor support structure may include adistribution board substrate and a contactor substrate mounted to thedistribution board substrate.

The apparatus may further include at least a first connectingarrangement that connects the contactor substrate to the distributionboard substrate, the first connecting arrangement including first andsecond connecting pieces with complementary interengaging formationsthat allow for movement of the contactor substrate relative to thedistribution board substrate in a first radial direction and restrictsmovement of the contactor substrate relative to the distribution boardsubstrate in a first tangential direction transverse to the first radialdirection.

In the apparatus, the distribution board may have a plurality of layershaving a plurality of different stiffnesses, one of the layers in a halfof the distribution board substrate opposing the terminals held by thecontactor support structure being stiffer than a majority of the layers.

The apparatus may further include cartridge including a cartridge framethat may be removably mountable to the apparatus frame, the contactorboard forming part of the cartridge, a contactor interface on thecontactor support structure, and a connector interface having a surfacefor connecting to a surface of the contactor interface.

In the apparatus, the cartridge may include a common subassembly and afirst unique contactor subassembly that may be replaceable with a secondunique contactor subassembly.

The apparatus may further include a pressure reduction passage incommunication with an area between the common subassembly and the secondunique contactor subassembly and having an outlet on an external side ofthe cartridge, and a pump connected to the outlet of the pressurereduction passage so as to reduce a pressure in the area between thecommon subassembly and the second unique contactor subassembly.

The invention further provides a cartridge, including a cartridge frame,formations on the cartridge frame for mounting the cartridge frame in afixed position to an apparatus frame, a contactor support structure, acontactor interface on the contactor support structure, a plurality ofterminals, held by the contactor support structure, for contactingcontacts on a device, and a plurality of conductors, held by thecontactor support structure, connecting the interface to the terminals.

The cartridge may further include an actuator connected between thecartridge frame and the contactor support structure, having first andsecond portions that may be movable relative to one another to move thecontactor support structure relative to the cartridge frame and towardthe surface of the holder so that the terminals may be urged againstcontacts of the device.

In the cartridge, the actuator may have a volume defined between thefirst and second components and a fluid line connected to the volume toallow air through the volume and thereby modify a size of the volume andmove the contactor support structure relative to the apparatus frame.

The cartridge may further include a pressure relief valve connected tothe fluid line to automatically release air from the fluid line thoughthe pressure relief valve when a pressure of the air in the fluid linereaches a predetermined value.

In the cartridge, the device may be a first device, further including aprocessor, a memory connected to the processor, and a computer programstored in the memory and executable by the processor to carry out amethod including reducing a pressure in the internal volume whilemaintaining the terminals in contact with the contacts, moving theholder relative to the apparatus frame to disengage the terminals fromthe contacts while maintaining the first and second components of theactuator in a substantially stationary relationship with one another,replacing the first device with a second device by removing the firstdevice from the holder and holding the second device against the surfaceof the holder, moving the holder relative to the frame to bring theterminals into contact with contacts of the second device while thefirst and second components of the actuator remain in substantially inthe stationary relationship relative to one another, increasing thepressure in the volume to urge the terminals against the contacts on thesecond device, and providing signals through the terminals and thecontacts of the second device to an integrated circuit of the seconddevice.

In the cartridge, the first and second portions of the actuator may be acylinder and a piston, respectively, the piston being located in thecylinder so that the cylinder and the piston jointly define a volume,further including, the fluid line being connected to the volume tomodify a pressure of the volume and move the piston relative to thecylinder.

The cartridge may further include a spring, and a spring adjustmentmechanism having a first portion secured to the piston and a secondportion connected to the spring, the spring adjustment mechanism beingadjustable to adjust a force of the spring and level the piston relativeto the cylinder.

In the cartridge, the actuator may include inflatable and deflatablebladder, the first and second portions of the actuator being opposingsides of the bladder.

The cartridge may further include a plurality of electrical componentsmounted on the contactor support structure.

In the cartridge, the electrical components may be mounted on a side onthe contactor support structure opposing the terminals held by thecontactor support structure.

The cartridge may further include a force distribution substrate, theelectrical components being located between the force distributionsubstrate and the force distribution substrate and the contactor supportstructure, and a stand-off component between the force distributionsubstrate and the contactor substrate to transfer force from thecontactor substrate to the force distribution substrate.

The cartridge may further include a subassembly having the contactorsupport structure, the terminals and a compensating piece with aprofiled surface that improves planarity of a surface of the subassemblyother than the profiled surface of the compensating piece.

In the cartridge, the contactor support structure may include adistribution board substrate and a contactor substrate mounted to thedistribution board substrate.

The cartridge may further include at least a first connectingarrangement that connects the contactor substrate to the distributionboard substrate, the first connecting arrangement including first andsecond connecting pieces with complementary interengaging formationsthat allow for movement of the contactor substrate relative to thedistribution board substrate in a first radial direction and restrictsmovement of the contactor substrate relative to the distribution boardsubstrate in a first tangential direction transverse to the first radialdirection.

In the cartridge, the distribution board may have a plurality of layershaving a plurality of different stiffnesses, one of the layers in a halfof the distribution board substrate opposing the terminals held by thecontactor support structure being stiffer than a majority of the layers.

In the cartridge, the cartridge may include a common subassembly and afirst unique contactor subassembly that may be replaceable with a secondunique contactor subassembly.

The cartridge may further include a pressure reduction passage incommunication with an area between the common subassembly and the secondunique contactor subassembly and having an outlet on an external side ofthe cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of example with reference tothe accompanying drawings wherein:

FIG. 1 is a perspective view of an apparatus, according to an embodimentof the invention, which can be used for full-wafer testing and/orburn-in and/or built-in self-testing;

FIG. 2 is a view similar to FIG. 1, wherein a thermal system frameportion is rotated approximately 45 degrees counterclockwise;

FIG. 3 is a sectioned perspective view from below, illustrating areplaceable cartridge forming part of the apparatus of FIGS. 1 and 2;

FIG. 4 is a cross-sectional side view, illustrating a contactor assemblyforming a lower part of the cartridge of FIG. 3;

FIG. 5 is a bottom plan view of one interface of contacts on adistribution board of the contactor assembly of FIG. 5;

FIG. 6 is a bottom plan view of the contactor assembly of FIG. 5,particularly illustrating a layout of a plurality of interfaces of FIG.5;

FIG. 7 is a cross-sectional side view of a portion of the cartridge ofFIG. 3, particularly illustrating an actuator mechanism that is used tomove the contactor assembly relative to a backing plate of a cartridgeframe, and further illustrating a wafer holder in the form of a waferchuck that holds a wafer;

FIG. 8 is a view similar to FIG. 7, after the wafer chuck has moved thewafer into a position below terminals of the contactor assembly;

FIG. 9 is a view similar to FIG. 8, after the actuator mechanism is usedto move the terminals into contact with contacts on the wafer;

FIG. 10 is a time chart illustrating a force that is created by a pistonof the actuator mechanism;

FIG. 11 is a cross-sectional side view, particularly illustrating onealignment and locking formation of the cartridge of FIG. 3 and onealignment and locking mechanism secured to an upper portion of a base ofa frame of the apparatus shown in FIGS. 1 and 2;

FIG. 12 is a view similar to FIG. 11, after the alignment and lockingmechanism is used to align the formation, and the formation is removablyengaged with the alignment and locking mechanism;

FIG. 13 is a cross-sectional side view, particularly illustrating onefirst connector set of the cartridge of FIG. 3, one second connector setsecured to a hinge portion of the frame of the apparatus of FIGS. 1 and2;

FIG. 14 is a partially cross-sectioned side view, illustrating a firstconnector module forming part of the first connector set of FIG. 13;

FIG. 15 is a view similar to FIG. 13, after an engager is used to rotatea spherical inner engagement surface of a first engagement componentforming part of the first connector set over a spherical engager formingpart of a second connector set;

FIG. 16 is a view similar to FIG. 15, after engagement of the firstconnector set with the second connector set;

FIG. 17 is a perspective view of the cartridge of FIG. 3, specificallyillustrating the layout and configuration of a plurality of firstconnector sets of FIG. 13;

FIG. 18 is a perspective view from below, illustrating a layout of aplurality of second connector sets of FIG. 13;

FIG. 19 is a perspective view of a portion of the apparatus shown inFIG. 2, wherein the thermal system frame portion is rotatedapproximately 135 degrees counterclockwise, and a test head frameportion is rotated approximately 90 degrees to the right;

FIG. 20 is an end view, illustrating in block diagram form the layout ofpower, driver, and pattern generator boards when viewed from the left inFIG. 19;

FIG. 21 is a cross-sectional side view parallel to two of the boardsillustrated in FIG. 20, further illustrating a thermal system that isused to cool the boards;

FIG. 22 is a block diagram of components of the apparatus of FIG. 1,further illustrating a computer system of the apparatus, the computersystem holding a configuration file representing a configuration of atester system of the apparatus;

FIG. 23 is a flow chart of how the apparatus of FIG. 19 is used;

FIGS. 24A and 24B show a block diagram illustrating a database structureof the configuration file;

FIG. 25 is a block diagram of a software assembly application that isused to construct the configuration file from a plurality of net files;

FIG. 26 is a flowchart of how the software assembly application of FIG.22 assembles the configuration file;

FIG. 27 is a block diagram of electrical components of the apparatus ofFIG. 1;

FIG. 28 is a block diagram of components of a power board illustrated inFIGS. 22 and 27, and connections made to the power board;

FIG. 29 is a circuit diagram illustrating components that are replicatedon the power board of FIG. 28;

FIG. 30 is a circuit diagram illustrating components that are replicatedon a driver board illustrated in FIGS. 22 and 27;

FIG. 31 is a circuit diagram illustrating a termination that is used inconventional design for purposes of damping a test signal;

FIG. 32 is a cross-sectional side view illustrating components of aright half of a replaceable cartridge, according to an alternativeembodiment of the invention, in exploded form;

FIG. 33 is a view similar to FIG. 32, after a distribution board and acontactor board are secured to one another and volume-defining rings aresecured to a lower backing plate of a piston and a force distributionsubstrate is secured to the piston;

FIG. 34 is a view similar to FIG. 33, showing assembly of common andunique subassemblies of the cartridge;

FIG. 35 is a top plan view, illustrating springs that are used to levelthe piston;

FIG. 36 is a perspective view, illustrating the use of stand-off layerwith openings over electric components;

FIG. 37 is a perspective view similar to FIG. 36, illustrating moreopenings in the stand-off layer;

FIG. 38 is a view similar to FIG. 34, showing right and left halves ofthe cartridge after final assembly and with a pump connected to thecartridge;

FIG. 39 is a cross-sectional side view of a portion marked “detail A” inFIG. 38;

FIG. 40 is a view similar to FIG. 38, illustrating how a force iscreated by the piston when two of the volume-defining rings are securedto the piston;

FIG. 41 is a view similar to FIG. 40, showing how a force is created bythe piston when only one of the volume-defining rings is secured to thepiston;

FIG. 42 is a cross-sectional side view similar to FIG. 40 of a furtherembodiment of the invention, utilizing an inflatable and deflatablebladder to reduce static friction;

FIG. 43 is a cross-sectional side view of a portion of the distributionboard;

FIG. 44 is a perspective view, showing a flexible attachment connectedto the distribution board of the cartridge;

FIG. 45 is a perspective view, showing components of the flexibleattachment in exploded form;

FIG. 46 is a cross-sectional side view of a flexible cable forming partof the flexible attachment;

FIG. 47 is a top plan view of a portion of the flexible cable,illustrating how ground conductors thereof are connected to one another;

FIG. 48 is a top plan view of two connectors with the flexible cableattached to the connectors;

FIG. 49 is a cross-sectional side view illustrating components of aright half of a replaceable cartridge, according to a further embodimentof the invention;

FIG. 50A is a cross-sectional side view of a portion of the cartridge ofFIG. 49 before a compensating piece is included;

FIG. 50B is a view similar to FIG. 50A, but including the compensatingpiece;

FIG. 51 is a computer rendering of a surface in FIG. 50A, illustratingmeasured differences in elevation of the surface;

FIG. 52 is a computer rendering illustrating different overlaying shimsthat are used for making the compensating piece;

FIG. 53 is a bottom perspective view showing inner and outer connectorarrangements that are used for maintaining contact between a contactorand a wafer both before and after heating of the contactor and the waferat different rates;

FIG. 54 is a bottom perspective view of the cartridge of FIG. 49,specifically illustrating positioning of more inner and outer connectorarrangements;

FIG. 55 is a top perspective view of a portion of a mounting ringforming part of the outer connector arrangement;

FIG. 56 is a bottom perspective view of the connector arrangements froman opposing side than shown in FIG. 53;

FIG. 57 is a cross-sectional side view of the cartridge of FIG. 49,specifically showing how the connector arrangement is assembled and alsoillustrating a pressure relief valve and an orifice that are used toprevent over pressurizing of a volume behind a piston;

FIG. 58 is a schematic view of a pneumatic system that is used tocontrol movement of the piston in FIG. 57; and

FIG. 59 show graphs of piston pressure, piston volume and translation,the state of an isolation valve, and the positioning of a wafer chuckover time in the operation of the pneumatic system of FIG. 58.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 of the accompanying drawings illustrate an apparatus 10,which is particularly suitable for full-wafer testing of microelectroniccircuits of unsingulated wafers and/or burn-in testing of unsingulatedwafers and/or built-in self-testing of unsingulated wafers. Theapparatus 10 includes a frame 12 and a number of modules mounted to theframe 12 including a wafer loader 14, a probing subassembly 16, acartridge 18, a test head 20, and a thermal system 24.

The frame 12 has a prober base portion 26, a thermal system frameportion 28, and a test head frame portion 30. The thermal system frameportion 28 is pivotally mounted to the prober base portion 26. The testhead frame portion 30 is pivotally mounted to the thermal system frameportion 28. The probing subassembly 16 and the cartridge 18 are mountedto lower and upper portions 32 and 34 respectively of the prober baseportion 26, and the test head 20 and the thermal system 24 are mountedto the test head frame portion 30 and the thermal system frame portion28 respectively.

The thermal system frame portion 28 can, for example, be pivoted betweena position as shown in FIG. 1 wherein the thermal system frame portion28 is over the prober base portion 26, and a position as shown in FIG. 2wherein the pivot arm portion is pivoted approximately 45 degreescounterclockwise to the left. Pivoting of the thermal system frameportion 28 into the position shown in FIG. 2 moves the test head 20 awayfrom the cartridge 18. Access is thereby gained to the cartridge 18 forpurposes of maintenance to or replacement of the cartridge 18.

As illustrated in FIG. 3, the cartridge 18 includes a cartridge frame38, alignment pins 40 for aligning and locking the cartridge frame 38 ina fixed position, a contactor assembly 42, a plurality of firstconnector sets 44, and a plurality of flexible attachments 46 connectingthe contactor assembly 42 to the first connector sets 44.

As shown in FIG. 4, the contactor assembly 42 includes a distributionboard 48, a contactor board 50, and fasteners 52 that secure thecontactor board 50 to the distribution board 48.

Distribution board 48 has a force distribution substrate 55, a thermalexpansion equalization substrate 57, and an electrical distributionsubstrate 54, a plurality of terminals 56 formed on the electricaldistribution substrate 54, a plurality of contacts 58 formed on theelectrical distribution substrate 54, and a plurality of conductors 60carried within the electrical distribution substrate 54. The terminals56 and the contacts 58 are formed on the same side but on differentareas of the electrical distribution substrate 54. Each conductor 60interconnects a respective one of the terminals 56 with a respective oneof the contacts 58.

The contactor board 50 includes a contactor substrate 62 having firstand second pieces 64 and 66, a collar 67, and a plurality of pins 68.One end of each pin 68 is inserted through an opening in the first piece64, and then inserted through an opening in the second piece 66. Eachpin 68 has a central body that is larger than its ends so that it isheld in place by the opening in the second piece 66. The collar 67 isused to align the first and second pieces 64 and 66 relative to oneanother. One end of each pin 68 forms a contact 70 that is placedagainst a respective terminal 56 of the distribution board 48. Anopposing end of each pin 68 forms a terminal 72 that can touch a contact74 on a wafer 76. The fasteners 52 may, for example, be bolts, eachhaving a shank that is inserted though an opening in the contactorsubstrate 62, and thread on the shank is then screwed into a threadedopening in the electrical distribution substrate 54. The electricaldistribution substrate 54, the contactor substrate 62, forcedistribution substrate 55, expansion equalization substrate 57, and thefasteners 52 jointly form a support structure 80 with the terminals 72extending from the support structure 80. The pins 68, terminals 56,conductors 60, and contacts 58 form conductive links to and from theterminals 72.

Each one of the flexible attachments 46 has a flexible nonconductiveouter layer 82, a plurality of conductors 84 held within the outer layer82 and separated from one another by the material of the outer layer 82,a plurality of open terminals 86 at ends of the respective conductors84, and a plurality of electrically conductive bumps 88, each on arespective one of the terminals 86. Each one of the conductive bumps 88is placed against a respective one of the contacts 58 of thedistribution board 48. A clamp piece 90 is placed over an end of theflexible attachment 46. Fasteners 91 are used to secure the clamp piece90 to the electrical distribution substrate 54, and provide a force thatclamps the end of the flexible attachment 46 between the clamp piece 90and the electrical distribution substrate 54.

As further shown in FIG. 5, the contacts 58 form an interface 92. Theinterface 92 has two parallel rows of the contacts 58. Two of thecontacts 58 g are ground contacts that extend from one of the rows tothe other and are located at opposing ends of the rows. Threadedopenings 94 are formed on opposing ends of the interface 92 into theelectrical distribution substrate 54. Each one of the fasteners 91 inFIG. 4 has a respective head and a respective threaded shank extendingfrom the head. The head rests on the clamp piece 90 and the shank isscrewed into one of the threaded openings 94 in FIG. 5. A compliantmember 93 is located between the clamp piece 90 and the flexiblenonconductive outer layer 82 to distribute a force created by the clamppiece 90 to ensure uniform contact by the electrically conductive bumps88.

Referring to FIG. 6, the electrical distribution substrate 54 is squareand has a periphery formed by four sides 98. The contactor substrate 62has a circular periphery 100 within the four sides 98. A plurality ofinterfaces 92 such as the interface 92 of FIG. 5 are provided on an areaof the electrical distribution substrate 54 outside the circularperiphery 100. The locations and orientations of the interfaces 92 areselected to provide a relatively dense configuration. The combinedlength of all the interfaces 92 is more than the length of the circularperiphery 100. The combined length of the interfaces 92 is also morethan the combined length of the four sides 98. The interfaces 92 in eachrespective quarter 102, 104, 106, and 108 are all aligned in the samedirection.

The interfaces 92 of the juxtaposed quarters 102 and 106 are each at anangle 110 of 45 degrees relative to a centerline 112 through thedistribution substrate 54. The interfaces of the juxtaposed quarters 104and 108 are each at an angle 114 of 135 degrees relative to thecenterline 112 as measured in the same direction as the angle 110.

Each one of the quarters 102, 104, 106, or 108 has ten of the interfaces92A to 92J. The interfaces 92C, 92D, and 92E are parallel to one anotherbut at different distances from a center point 116 of the contactorsubstrate 62. The interfaces 92F, 92G, and 92H are parallel to oneanother but at different distances from the center point 116. Theinterfaces 92C and 92F are in line with one another, as are theinterfaces 92D and 92G and the interfaces 92E and 92H. The interfaces92B and 92I are in line with one another but form a row that is closerto the center point 116 than the row formed by the interfaces 92C and92F. The interfaces 92B and 92I are also spaced further from one anotherthan the interfaces 92C and 92F. The interfaces 92A and 92J also form arow that is closer to the center point 116 than the row formed by theinterfaces 92B and 92I.

Each one of the quarters 102, 104, 106, and 108 has an arrangement often of the interfaces 92 that is similar to the arrangement ofinterfaces 92A to 92J. The arrangement is rotated through 90 degreesabout the center point 116 when moving from the quarter 108 to thequarter 102. Similarly, the arrangement is rotated through another 90degrees when moving from the quarter 102 to the quarter 104, etc.

A respective flexible attachment 46 is connected to each respective oneof the interfaces 92. The arrangement of the interfaces 92 allows for“fanning-in” or “fanning-out” of a large number of electrical paths toor from a relatively dense arrangement of the terminals 72 of thecontactor board 50.

Referring again to FIG. 3, the cartridge frame 38 includes a lowerbacking plate 120, upper support pieces 122, and connecting pieces 124that mount the upper support pieces 122 to the backing plate 120. Thecartridge 18 further includes an actuator mechanism 126 for moving thecontactor assembly 42 relatively with respect to the cartridge frame 38,and a travel sensor 128.

FIG. 7 illustrates the actuator mechanism 126, travel sensor 128, and awafer chuck 130 holding a wafer 76. A cylinder 132 is manufactured inthe backing plate 120. The cylinder 132 has an outer surface 134 and anupper surface 138. A ring-shaped sliding piston 140 is inserted into thecylinder 132. A lower surface of the piston 140 is attached to thesupport structure 80. A fixed ring-shaped piston 136 is inserted intothe center of the piston 140. An upper surface of the fixed ring-shapedpiston 136 is attached to the backing plate 120. The support structure80 is thus connected through the piston 140, fixed ring-shaped piston136, and cylinder 132 of the actuator mechanism 126 to the backing plate120. By locating the actuator mechanism 126 between the backing plate120 and the support structure 80, the actuator mechanism 126 can movethe contactor assembly 42 relatively with respect to the backing plate120. A fluid passage 142 is manufactured in the backing plate 120. Thefluid passage 142 extends from an external surface of the backing plate120 to a location above an upper surface of the piston 140. A fluid line144 is connected to the fluid passage 142. Pressurized air or a vacuumpressure can be provided through the fluid line 144 and fluid passage142 to an upper surface of the piston 140.

The travel sensor 128 has an outer portion 146 attached to the supportstructure 80, and an inner portion 148 attached to the backing plate120. Relative movement between the outer portion 146 and the innerportion 148 results in a change of inductance (or capacitance) betweenthe outer portion 146 and the inner portion 148. The inductance (orcapacitance) can be measured to provide an indication of how far theouter portion 146 travels with respect to the inner portion 148. Theouter portion 146 fits within a circular opening in the backing plate,and the outer portion 146 additionally serves as a guide for movement ofthe contactor assembly 42 relative to the backing plate 120.

The wafer chuck 130 forms part of the probing subassembly 16 illustratedin FIGS. 1 and 2. The wafer chuck 130 is mounted for movement inhorizontal x- and y-directions and movement in a vertical z-direction tothe prober base portion 26 of FIGS. 1 and 2.

As illustrated in FIG. 8, the wafer chuck 130 with the wafer 76 thereonis moved in x- and y-directions until the wafer 76 is directly below thecontactor board 50. The wafer chuck 130 is then moved verticallyupwardly in a z-direction towards the contactor board 50. Each one ofthe terminals 72 is aligned with a respective one of the contacts on thewafer 76. The terminals 72, however, do not at this stage touch thecontacts on the wafer 76.

As shown in FIG. 9, the actuator mechanism 126 is used to bring theterminals 72 into contact with the contacts on the wafer 76. Pressurizedair is provided though the fluid line 144 and the fluid passage 142 intoa volume defined by the surfaces 134 and 138 of the cylinder 132, anouter surface of the fixed ring-shaped piston 136, and an upper surfaceof the piston 140. The pressurized air acts on the upper surface of thepiston 140 so that the piston 140 is moved downward relative to thebacking plate 120. The piston 140 also moves the contactor assembly 42downward until the terminals 72 come into contact with the contacts onthe wafer 76. The terminals 72 are resiliently depressible againstspring forces of the pins that they form part of. The spring forcesjointly serve to counteract a force created by the pressure on thepiston 140.

FIG. 10 shows the force that is created by the piston 140. No force actson the terminals in FIGS. 7 and 8. In FIG. 9, the force is increasedfrom zero to a predetermined force. This predetermined force can becalculated by multiplying the pressure and the area of the upper surfaceof the piston 140. The forces created by the terminals 72 are highlycontrollable because the pressure is highly controllable. Thepredetermined maximum force can easily be modified from one applicationto another. When the forces are applied by the terminals 72, electricsignals, power, and ground are provided through the terminals 72 to andfrom the wafer 76. Integrated circuits on the wafer 76 are therebytested. Once testing is completed, the pressure is relieved so that theforces exercised by the terminals 72 are again reduced to zero. Anegative pressure is then applied, which moves the contactor assembly 42away from the wafer 76 into the position shown in FIG. 8. The wafer 76is then removed by the wafer chuck 130 and the wafer 76 is replaced withanother wafer on the wafer chuck 130.

It will be appreciated that the order and speed of moving the waferchuck 130 relative to the contactor board 50 actuating the actuatormechanism 126 to bring the terminals 72 into contact with the contactsof the wafer 76 can be varied. Differing contact algorithms can be usedto move the wafer chuck 130 and actuate the actuator mechanism 126 toachieve optimal contact (e.g., good electrical contact, least paddamage, etc.) for different types of wafers.

The travel sensor 128 allows the pressure of the piston 140 to be set sothat the piston 140 is roughly in the middle of its stroke when itcontacts the wafer 76. Wafers having differing contactor technologiesand/or numbers of contact points may be used with the apparatus 10.Different contact technologies often require a different force per pinto ensure wafer contact, and may also have different contactor heights.A different total force may be required to be applied to the contactorto make good contact with the wafer 76. The travel sensor 128 can beused to measure the distance the piston 140 has extended the contactortoward the wafer 76 under test. Thus, wafers having these varying typesof contactors can be tested using the same apparatus 10.

FIG. 11 illustrates an alignment and locking mechanism 152 mounted tothe upper portion 34 of the frame 12 in FIGS. 1 and 2, and one of thealignment pins 40 mounted to the cartridge frame 38.

The alignment and locking mechanism 152 includes an outer sleeve 154, analignment piece 156, a piston 158, a fluid line 160, and a lockingactuator 162.

The alignment piece 156 has an alignment opening 164 formed therein. Thealignment opening 164 has a conical shape so that an upper horizontalcross-section thereof is larger than a lower cross-section thereof. Thealignment piece 156 is mounted to an upper end of the outer sleeve 154and extends downwardly into the outer sleeve 154.

The piston 158 is located within a lower portion of the outer sleeve 154and can slide up and down within the outer sleeve 154. A cavity 166 isdefined within the outer sleeve 154 and by a lower surface of the piston158. The fluid line 160 is connected to the cavity 166. Positive andnegative pressure can be provided through the fluid line 160 to thecavity 166. Positive pressure causes upward movement of the piston 158,and negative pressure causes the piston 158 to move down.

The locking actuator 162 has a plurality of spherical locking members168 and a locking actuator 170. The locking actuator 170 is mounted tothe piston 158 so that it can move vertically up and down together withthe piston 158. The locking actuator 170 has an internal surface 172that makes contact with the spherical locking members 168. The surface172 is conical so that movement of the locking actuator 170 betweenraised and lowered positions causes corresponding movement of thespherical locking members 168 toward and away from one another.

The alignment pin 40 includes a positioning pin 174 with a recessedformation 176 formed at a location distant from an end of thepositioning pin 174. The cartridge frame 38 is moved so that thepositioning pin 174 is roughly located over the alignment opening 164.When the cartridge frame 38 is lowered into the position shown in FIG.11, an end of the slightly misaligned positioning pin 174 can slide on asurface of the alignment opening 164 so that a center line of thepositioning pin 174 moves towards a center line of the alignment opening164. The piston 158 and the locking actuator 162 are in a loweredposition to allow for movement of a larger end of the positioning pin174 through an opening defined by the spherical locking members 168.

FIG. 12 illustrates the components of FIG. 11 after the alignment pin 40is lowered all the way and engaged with the alignment and lockingmechanism 152. A conical surface on the alignment pin 40 contacts theconical surface of the alignment opening 164, thereby further promotingcorrect alignment of the center lines of the positioning pin 174 and thealignment opening 164. The recessed formation 176 on the positioning pin174 is now at the same elevation as the spherical locking members 168.The piston 158 and the locking actuator 170 are elevated so that thespherical locking members 168 engage with the recessed formation 176.The positioning pin 174 is thereby engaged with the spherical lockingmembers 168 of the alignment and locking mechanism 152.

The positioning pin 174 can be released from the alignment and lockingmechanism 152 by first lowering the piston 158 so that the sphericallocking members 168 disengage from the recessed formation 176, and thenlifting the cartridge frame 38 together with the positioning pin 174 outof the alignment opening 164. It may from time to time be required thata cartridge 18 be temporarily removed for purposes of maintenance orreconfiguration, or be replaced with another cartridge. The alignmentpin 40 and the alignment and locking mechanism 152 allow for quickremoval and replacement of cartridges.

FIG. 3 illustrates one and a piece of the alignment pins 40. Only apiece of the cartridge 18 is illustrated in FIG. 3, and the entirecartridge is in fact symmetrical about the section through one of thealignment pins 40. The other piece of the sectioned alignment pin andanother one of the alignment pins are not shown. There are thus a totalof three of the alignment pins 40 respectively at corners of a triangle.Each one of the alignment pins 40 engages with a corresponding alignmentand locking mechanism 152. The three alignment and locking mechanisms152 are all simultaneously and remotely actuable from a common pressuresource connected to corresponding fluid lines 160, to cause simultaneousengagement or disengagement of all three locking alignment pins 40.

As previously mentioned with reference to FIGS. 1 and 2, the test head20 can be moved to the position shown in FIG. 2 for purposes ofmaintenance to the cartridge 18. The cartridge 18 can also be replaced,as discussed with reference to FIGS. 11 and 12. Following maintenanceand/or replacement of the cartridge 18, the test head 20 is pivoted ontothe cartridge into the position shown in FIG. 1.

FIG. 13 illustrates portions of the test head and cartridge 18 after thetest head 20 is moved down onto the cartridge 18, i.e., from theposition shown in FIG. 2 into the position shown in FIG. 1. The testhead 20 has a second connector set 180 and an engager 182 mounted to thetest head frame portion 30 of the frame 12 of FIG. 1. The secondconnector set 180 is initially disengaged from one of the firstconnector sets 44 of the cartridge 18.

The first connector set 44 includes a connector block support piece 184,a first connector module 186, and a first engagement component 188.

The first connector module 186 includes a first connector block 190 anda plurality of septa 192. The septa 192 are held in a side-by-siderelationship by the first connector block 190. FIG. 14 illustrates oneof the septa 192 in more detail. A plurality of conductors is formedbehind one another into the paper against each septum 192. Eachconductor includes a terminal 196 at a lower edge of the septum 192, acontact 198 at an upper edge of the septum 192, and an electricallyconductive lead 200 interconnecting the terminal 196 with the contact198.

Referring again to FIG. 13, a number of the flexible attachments 46 areattached through respective connectors 202 to the terminals 196 of FIG.14. The septa 192 provide for a dense arrangement of the terminals 196and contacts 198 held by the first connector block 190.

The first connector module 186 is inserted into the connector blocksupport piece 184 with the first connector block 190 contacting an innerportion of the connector block support piece 184. The first connectormodule 186 is then secured to the connector block support piece 184 byreleasable means so as to again allow for removal of the first connectormodule 186 from the connector block support piece 184.

The first engagement component 188 has inner and outer portions 204 and206 respectively. The inner portion 204 is mounted to an outer portionof the connector block support piece 184 for pivotal movement about ahorizontal axis 208. A spring 210 biases the first engagement component188 in a counterclockwise direction 212. The outer portion 206 has aspherical inner engagement surface 214 and a groove 216 as formed intothe engagement surface 214.

A slider pin 218 is secured to and extends vertically upwardly from oneof the upper support pieces 122 of the cartridge frame 38. Acomplementary slider opening 220 is formed vertically through theconnector block support piece 184. The slider opening 220 is positionedover the slider pin 218, and the first connector set 44 is moved downuntil the connector block support piece 184 rests on the upper supportpiece 122. The first connector set 44 is thereby held by the slider pin218 of the cartridge frame 38 and prevented from movement in horizontalx- and y-directions. The first connector set 44 can still be removedfrom the cartridge frame 38 by lifting the first connector set 44 out ofthe slider pin 218, for purposes of maintenance or reconfiguration.

The second connector set 180 includes a subframe 222, a second connectormodule 224, a cylinder 226, a piston 228, a rod 230, a spherical engager232, a connecting piece 234, and first and second supply lines 236 and238, respectively.

The subframe 222 is mounted to the test head frame portion 30. Thesecond connector set 180 is mounted through the subframe 222 to the testhead frame portion 30. The second connector set 180 has a secondconnector block 240 and a plurality of printed circuit boards 242mounted in a side-by-side relationship to the second connector block240. Each one of the printed circuit boards 242 has a respectivesubstrate, terminals on a lower edge of the substrate, contacts at anupper edge of the substrate, and electrically conductive traces, eachconnecting a respective terminal with a respective contact. The secondconnector block 240 is releasably held within the subframe 222 andsecured to the subframe 222 with releasable means.

The cylinder 226 is secured to the subframe 222. The piston 228 islocated within the cylinder 226 and is movable in vertically upward anddownward directions within the cylinder 226. First and second cavitiesare defined within the cylinder 226 respectively above and below thepiston 228, and the first and second supply lines 236 and 238 areconnected to the first and second cavities, respectively.

An upper end of the rod 230 is secured to a piston 228. The rod 230extends downwardly from the piston 228 through an opening in a base ofthe cylinder 226. The spherical engager 232 is secured via theconnecting piece 234 to a lower end of the rod 230. The connecting piece234 has a smaller diameter than either the rod 230 or the sphericalengager 232.

The engager 182 includes a plate 246 that is mounted to the subframe 222for pivotal movement about a horizontal axis 248, an actuator assembly201, and a link mechanism 252 connecting the plate 246 to the actuatorassembly 201. The actuator assembly 201 includes an actuator 250, aconnecting rod 253, an actuator pivot 251, and a rod pivot 255.

As previously mentioned, the second connector set 180 is initiallydisengaged from the first connector set 44. The second connector module224 is thus disengaged from the first connector module 186, and thespherical engager 232 is also disengaged from the first engagementcomponent 188. Pressurized air is provided through the first supply line236 while air is vented from the second supply line 238, so that thepiston 228 moves in a downward direction within the cylinder 226.Downward movement of the piston 228 extends the rod 230 further out ofthe cylinder 226 and moves the spherical engager 232 closer to thecartridge 18.

As illustrated in FIG. 15, the actuator assembly 201 is operated so thatthe link mechanism 252 moves the plate 246 in a counterclockwisedirection 254. The plate 246 comes into contact with an outer surface256 of the first engagement component 188. Further movement of the plate246 rotates the first engagement component 188 in a clockwise direction258 and in a camming action. A fork defined by the groove 216 moves overthe connecting piece 234, and the engagement surface 214 moves into aposition over at the spherical engager 232.

As illustrated in FIG. 16, pressurized air is provided through thesecond supply line 238, and air is vented through the first supply line236 so that the piston 228 moves in a vertically upward direction. Therod 230 retracts in an upward direction into the cylinder 226. An uppersurface of the spherical engager 232 engages with the engagement surface214 and moves the first engagement component 188 towards the cylinder226. The first connector set 44 lifts off the upper support piece 122 ofthe cartridge frame 38, and the connector block support piece 184 slidesup the slider pin 218.

The pressurized air provided through the second supply line 238 alsocreates a force that is sufficiently large to overcome an insertionforce required to mate the first connector module 186 with the secondconnector module 224. Each one of the septa 192 enters into a gapbetween two of the printed circuit boards 242. Gaps between the contacts198 on the septa 192 and the gaps between the printed circuit boards 242are sufficiently small so that an interference fit is required to insertthe septa 192 between the printed circuit boards 242. Once the insertionforce is overcome and the septa 192 are located between the printedcircuit boards 242, each one of the contacts 198 is located against acorresponding terminal on a lower edge of one of the printed circuitboards 242.

The pressurized air provided through the second supply line 238 can beremoved after the first and second connector modules 186 and 224 aremated. The first and second connector modules 186 and 224 can bedisengaged from one another by providing pressurized air through thefirst supply line 236 so that the first connector set 44 moves into theposition as shown in FIG. 15. The actuator assembly 201 is then operatedand the plate 246 moves into the position shown in FIG. 13. The spring210 biases the first engagement component 188 in the counterclockwisedirection 212 away from the spherical engager 232. The rod 230 is thentypically again retracted into the cylinder 226.

As illustrated in FIG. 17, cartridge frame 38 has four of the uppersupport pieces 122, and a respective pair of the upper support pieces122 carries a respective column of the first connector sets 44. Thecolumns are located next to one another so that a respective pair of thefirst connector sets 44 is in a respective row. There can be a total of16 rows in each of the two columns, thus potentially forming an array of32 of the first connector sets 44.

Each one of the first connector sets 44 is symmetrical on the left andthe right. The connector block support piece 184 entirely surrounds thefirst connector module 186, and two slider openings (220 in FIG. 13) areprovided at opposing ends of the connector block support piece 184.Slider pins 218 are provided on all four of the upper support pieces122, and each respective connector block support piece 184 has twoslider openings 220 respectively located over two of the slider pins218.

As shown in FIG. 18, an array of second connector modules 224 isprovided, matching the array of first connector modules 186 of FIG. 17.Two spherical engagers 232 are located on opposing sides of each one ofthe second connector modules 224. In use, a respective pair of sphericalengagers 232 is used to engage one of the first connector modules 186with one of the second connector modules 224, independently of the otherconnector modules. One of the first connector modules 186 is engagedwith one of the second connector modules 224, whereafter another one ofthe first connector modules 186 is engaged with another one of thesecond connector modules 224, etc. By staggering the engagement of arespective first connector module 186 with a respective second connectormodule 224, forces on the subframe 222 and other pieces of the frame 12of FIG. 1 can be kept within their design parameters.

Each one of the plates 246 is located adjacent a plurality of thespherical engagers 232. Movement of a respective one of the plates 246causes the respective plate 246 to contact and simultaneously pivot aplurality of the first engagement components 188 of FIG. 13 over aplurality of respective ones of the spherical engagers 232.

Referring to FIGS. 18 and 19 in combination, each one of the secondconnector modules 224 is mounted to respective pattern generator,driver, and power boards, 260, 262, and 264 respectively, each residingin a respective slot of a base structure 266. As specifically shown inFIG. 19, access can be gained to the boards 260, 262, and 264 byrotating the thermal system frame portion 28 together with the test headframe portion 30 an additional 135 degrees counterclockwise to the leftwhen compared to FIG. 2, and then rotating the test head frame portion30 relative to the thermal system frame portion 28 90 degrees clockwiseto the right. The thermal system 24 is then positioned on the ground andthe test head 20 in a vertical orientation. The boards 260, 262, and 264are all accessible from the left within the test head 20 because thetest head 20 and the thermal system 24 have been separated from oneanother. The boards 260, 262, and 264 that reside in the slots of thebase structure 266 are then removable and replaceable, and other boardscan be added for purposes of reconfiguration.

Each one of the slots can only carry one particular type of board 260,262, or 264. The base structure 266 is configurable so that slots areconfigurable to allow for more or fewer of a particular board, or tomodify the locations of particular boards. Once the slots are inserted,they are typically not replaced over the life of the apparatus 10. Thenumber of boards 260, 262, and 264 that are used can still be configuredfrom one application to the next. FIG. 20 illustrates an example of alayout of slots in the test head 20. The particular layout of slots ofFIG. 20 allows for the use of two pattern generator boards 260, one onthe left and one on the right; six driver boards 262, three on the leftand three on the right; and 24 power boards 264, twelve on the left andtwelve on the right.

After the boards 260, 262, and 264 are inserted into the slots asdiscussed with reference to FIGS. 19 and 20, the apparatus is firstmoved into the configuration illustrated in FIG. 2 with the thermalsystem 24 above the test head 20, and then into the configurationillustrated in FIG. 1, with the components of the test head 20electrically connected to the components of the cartridge 18 in FIG. 2.

Referring specifically to FIG. 1, what should be noted is that thethermal system 24 does not rest on the test head 20. Any vibrationscaused by components of the thermal system 24 can thus not be directlytransferred to the test head 20. The test head 20 and the thermal system24 are held in the relative orientation shown in FIG. 1, with thethermal system 24 above the test head 20 by the thermal system frameportion 28 and the test head frame portion 30, respectively, of theframe 12. The frame 12 is relatively heavy and has a rigid construction,and effectively dampens any vibrations created by components of thethermal system 24. The vibrations substantially do not reach thecomponents of the test head 20.

FIG. 21 illustrates how the thermal system 24 cools components of thetest head 20. FIG. 21 is a partial cross-sectional view parallel to aplane of one of the boards 260, 262, and 264 of FIG. 20, and shows oneof the driver boards 262 and one of the power boards 264 inserted intotheir respective slots of the base structure 266 of the test head 20.The test head 20 further has two manifold panels 268 mounted on opposingsides and at upper portions of the base structure 266. The basestructure 266 has openings between the slots that allow for air to flowfrom the manifold panels 268 inward to the boards 262 and 264, and thenfrom the boards 262 and 264 to an upper end exhaust 270.

The thermal system 24 includes an outer shell 272, four recirculationfans 274 (only two of the recirculation fans 274 are shown in FIG. 21;the other two recirculation fans are located behind the recirculationfans 274 that are shown in FIG. 21), and two heat exchangers 276. Theair leaving the upper end exhaust 270 is sucked through therecirculation fans 274 into the outer shell 272. Recirculation fans 274then force the air through the heat exchangers 276, whereafter the airenters through upper end inlets 278 defined by the manifold panels 268.By recirculating the air, heat convects from the boards 262 and 264 tothe heat exchangers 276. As is commonly known, each heat exchanger 276includes a plurality of fins 280 and tubing 282 connecting the fins 280to one another. A cooling fluid such as liquid water is pumped throughthe tubing 282. The heat convects to the fins 280. The heat conductsfrom the fins 280 to the tubing 282. The heat then convects from thetubing 282 to the water and is pumped away.

What should be noted is that there is no physical contact between anycomponents of the thermal system 24 and any components of the test head20. Only a small gap 284 is defined between the outer shell 272 and themanifold panel 268. A seal is typically located in the gap 284, and ismade of a compliant material so that any vibrations transferred by therecirculation fan 274 to the outer shell 272 do not transfer to themanifold panels 268. Guide panels 286 form part of the thermal system24, and serve to prevent the air from entering the test head 20 beforefirst passing through the recirculation fans 274 and the heat exchangers276.

FIG. 22 illustrates software and hardware components of the apparatus 10of FIG. 1 that cooperate and that are matched to one another forfanning-out and fanning-in of electric signals, power, and ground. Zonesare defined, wherein each zone includes one pattern generator board 260,one or more driver boards 262, and one or more power boards 264connected to one another. Each board 260, 262, and 264 has a number ofresources or channels. In particular, a driver board 262 has a number ofinput/output channels, and the power board 264 has a number of powerchannels. The number of boards 260, 262, and 264 and the way that theyare connected to one another are configurable, depending on therequirements of integrated circuits of devices 300 and the layout of thedevices 300 of the wafer 76.

An interconnection scheme 302 connects the driver and power boards 262and 264 to contacts on the devices 300. The interconnection scheme 302includes the electrical paths formed by conductors within the cartridge18 of FIG. 3. The interconnection scheme 302 is also configurable, aswill be appreciated from the foregoing description of the cartridge 18.The boards 260, 262, and 264 and the interconnection scheme 302 arehereinafter jointly referred to as a tester system 304.

A local controller 306 is used to provide test instructions to thetester system 304, and is then used to upload and process test resultsfrom the tester system 304. The local controller 306 has memory, andstored in the memory are a test program 308, a configuration file 310, atest application 312, a test results file 314, a processing application316, and a test report 318.

Reference should now be made to FIGS. 22 and 23 in combination. The testprogram 308 has a series of instructions written by a test programmer totest one of the devices 300 (step 400). The following is an extract ofsuch a program:

setdps (“v NORMAL 1”, “Vcc”, 3.0 V, 0.0 V, 11.0 V);

setdps (“v NORMAL 1”, “Vcd”, 4 V, 0.0 V, 11.0 V);

setsps (“v NORMAL 1”, “Vio”, 0 V, 3.3 V);

setsps (“v NORMAL 1”, “Vclk”, 0 V, 3.3 V);

setsps (“v NORMAL 1”, “Vcs”, 0 V, 3.3 V);

setpps (“v NORMAL 1”, “Term 1”, 1.0);

settps (“v NORMAL 1”, “Term 2”, 1.0);

setthps (“v NORMAL 1”, “CompH”, 1.5);

setthps (“v NORMAL 1”, “CompL”, 0.9).

The test application 312 utilizes the test program 308 and data from theconfiguration file 310 and data from the test results file 314 toprovide instructions to the boards 260, 262, and 264 (step 402). Theboards 260, 262, and 264 then provide electric signals, power, or groundthrough respective conductors of the interconnection scheme 302 (step404). The configuration file 310 has data representing a relationshipbetween the channels of the boards 260, 262, and 264 and the contacts ofthe devices 300. The configuration file 310 will be different from oneconfiguration assembly to another configuration assembly of the testersystem 304. The configuration file 310 thus represents how theinstructions of the test program 308 are fanned out through the testersystem 304 to the devices 300. Each device 300 is tested with the sametest program 308 (step 406), although the voltage and signal levels maybe modified based upon the test results file 314.

The following table is an extract of the configuration file 310 withfield names listed at the top of each column:

PWR ZONE SLOT CHANNEL RAB MODULE CHANNEL CONN PAD TERM COMMON NUMBERNUMBER TYPE NUMBER NUMBER NUMBER COLUMN ROW TYPE LABEL LABEL KEY MASK 229 HVOL 1 1 0 5 16 D CE 0 0 0 2 22 DRV_CS −1 −1 0 1 20 D OE CS_0 0 0 1 6DRV_CS −1 −1 0 37 15 D OE CS_0 0 0 1 6 DRV_UCLK −1 −1 0 35 15 D DQ1 A_00 0 2 22 DRV_UCLK −1 −1 0 7 20 D DQ1 A_0 0 0 2 22 DRV_UCLK −1 −1 1 20 25D DQ1 B_1 0 0 2 22 DRV_IO −1 −1 1 2 21 D DQ7 I/O_1 0 0 1 6 DRV_UCLK −1−1 1 15 10 D DQ1 B_1 0 0 2 22 DRV_CS −1 −1 1 3 21 D OE CS_1 0 0 1 6DRV_CS −1 −1 1 32 14 D OE CS_1 0 0 1 6 DRV_UCLK −1 −1 1 15 2 D DQ1 B_1 00 1 6 DRV_UCLK −1 −1 1 17 14 D DQ1 B_1 0 0 1 6 DRV_IO −1 −1 1 37 13 DDQ7 I/O_1 0 0 1 6 DRV_CS −1 −1 1 28 6 D OE CS_1 0 0 1 6 DRV_UCLK −1 −1 116 14 D DQ1 B_1 0 0 2 22 DRV_UCLK −1 −1 1 6 25 D DQ1 A_1 0 0 2 22 DRV_CS−1 −1 1 10 17 D OE CS_1 0 0 2 22 DRV_CS −1 −1 1 11 21 D OE CS_1 0 0 2 22DRV_UCLK −1 −1 1 21 21 D DQ1 B_1 0 0 1 6 DRV_UCLK −1 −1 1 16 10 D DQ1B_1 0 0 2 22 DRV_CS −1 −1 1 2 21 D OE CS_1 0 0 2 22 DRV_UCLK −1 −1 1 2317 D DQ1 B_1 0 0 2 22 DRV_CS −1 −1 1 1 21 D OE CS_1 0 0 2 22 DRV_CS −1−1 1 9 17 D OE CS_1 0 0 1 6 DRV_UCLK −1 −1 1 16 2 D DQ1 B_1 0 0 1 6DRV_CS −1 −1 1 27 3 D OE CS_1 0 0 1 6 DRV_UCLK −1 −1 1 36 14 D DQ1 A_1 00 2 22 DRV_CS −1 −1 1 16 32 D OE CS_1 0 0 1 6 DRV_UCLK −1 −1 1 18 6 DDQ1 B_1 0 0 1 6 DRV_CS −1 −1 1 34 10 D OE CS_1 0 0 2 22 DRV_UCLK −1 −1 16 21 D DQ1 A_1 0 0 1 6 DRV_CS −1 −1 1 31 14 D OE CS_1 0 0 1 6 DRV_UCLK−1 −1 1 32 6 D DQ1 A_1 0 0 2 22 DRV_UCLK −1 −1 1 8 25 D DQ1 A_1 0 0

The fields at the top of the columns of the table above stand for thefollowing:

ZONE NUMBER: index to indicate membership to a pattern zone, determinedby pattern generator board 260.

SLOT NUMBER: location of a driver or power board 262 or 264.

CHANNEL TYPE: type of hardware resource to be used.

RAB NUMBER: index of reference and acquisition module on the power board264, or −1 if not applicable.

PWR MODULE NUMBER: power module on power board 264.

CHANNEL NUMBER: resource index of given board 262 or 264.

COLUMN, ROW: position of the base structure 266 on the wafer (ortestboard).

CONN TYPE: connection type; D for device, or T for termination; whethera resource influences a device directly, or provides auxiliaryelectrical characteristics to the test assembly.

PAD LABEL: designator for the terminal 72 or pin 68 that the resource isconnected to; this label is then used for programming purposes.

TERM LABEL: option label for a termination pin.

COMMON KEY: option sort key.

MASK: field to determine whether a device should be tested or not.

Some resources are provided separately to each of the devices 300. Forexample, there may be a total of 600 of the devices 300, and each devicemay require a separate input/output line connected through theinterconnection scheme 302. Other resources may be shared in order toreduce the number of electrical paths that are provided through theinterconnection scheme 302. For example, a single input/output line 320can be provided through the interconnection scheme 302, and at the lastlevel within the interconnection scheme 302 be fanned to a set (or all)of the devices 300. An input/output signal is thus provided to all thedevices 300 of the set. A chip select line 322 can be accessed to selecta subset of the devices of the set to which the input/output line 320 isconnected. Unique chip select line combinations are then grouped intochip select states.

FIGS. 24A and 24B illustrate the data structure of the configurationfile 310 (“cartconf”). The configuration file 310 includes both a waferrequirement data structure (wafer_reqs) and a shared resources map(cs_map) representing the chip select states. Descriptions of therespective fields and what the fields represent are described in FIGS.24A and 24B.

Again referring to FIGS. 22 and 23, a response from each one of thedevices 300 is provided through the interconnection scheme 302 andstored in the memory of the driver and power boards 262 and 264 (step408). The system software uploads the responses from the driver andpower boards 262 and 264 into the test results file 314 (step 410). Thetest results file 314 has raw data wherein the test results of all thedevices 300 are collated. The test results file 314 is provided to aprocessing application 316. The processing application 316 utilizes theconfiguration file 310 to interpret the test results file 314 in such amanner that the test results of individual ones of the devices 300 areextracted from the test results file 314 (step 412). The processingapplication 316 then publishes the test report 318 (step 414). The testreport 318 is typically a two-dimensional map on a computer screen withcells representing the devices 300, wherein functioning and defectivedevices are shown in different colors. The test results file 314 is alsoto be used by the test application 312 to modify the instructionsprovided to boards 260, 262, and 264.

FIG. 25 illustrates a software assembly application 420 that is used forconstructing the configuration file 312 of FIG. 19. The application 420includes a plurality of net files 422, an input module 424, and anassembly module 426. The net files 422 each represent a scheme ofcurrent passing through conductors of a respective electricalsubassembly. For example, the net file 422A is a pattern generator boardnet file representing the flow of current through one of the patterngenerator boards 260 of FIG. 19. Similarly, the driver board net file422B and power board net file 422C respectively represent flow ofcurrent through conductors through one of the driver boards 262 and oneof the power boards 264. The interconnection scheme 302 also hasmultiple components, and a respective net file 422D or 422E representsflow of current through a respective component of the interconnectionscheme 302.

Referring now to FIGS. 25 and 26 in combination, the net files 422 arefirst stored in the memory of a computer system on which the softwareassembly application 418 resides (step 450). The input module 424 has aninterface with a list of the components that can make up the testersystem 304. The list includes one pattern generator board, one driverboard, one power board, and one type of each component that can make upthe interconnection scheme 302. The input module 424 also allows anoperator to select how many of the components on the list are used toassemble the tester system 304, and how the components are connected toone another. For example, the operator can select two pattern generatorboards and three driver boards, one of the driver boards being connectedto one of the pattern generator boards and the other two driver boardsbeing connected to the other pattern generator board (step 452).

The assembly module 426 then uses the input provided by the operator viathe input module 424 and the net files 422 to assemble the configurationfile 310. In the given example, the assembly module 426 will constructthe configuration file 310 so that it has data representing two patterngenerator net files 422A and three driver board net files 422B, with onedriver board net file 422B being associated with one pattern generatorboard net file 422A and the other two pattern generator net files 422Bbeing associated with the other pattern generator board net file 422A(step 454). The configuration file 310 can then be transferred from thecomputer system on which the software assembly application 420 residesto the local controller 306 of FIG. 22.

FIG. 27 illustrates some of the components hereinbefore described andsome additional components of the apparatus 10. The componentshereinbefore described include the cartridge 18 that has the contactorassembly 42, the flexible attachments 46, two of the power boards 264,one of the driver boards 262, one of the pattern generator boards 260,and the local controller 306. Two types of power boards 264V and 264Care used, for high voltage and high current respectively. Each powerboard 264V or 264C has eight logical groups of 64 channels, andtherefore 512 channels in total. The high-voltage power board 264V canprovide a voltage output of 0.5 V to 12 V at a current of at least 200mA for each channel. The high-current power board 264C can provide anoutput of 0.1 V to 5 V at a current of at least 500 mA. The locations ofthe boards 260, 262, and 264 have been described with reference to FIG.20.

Each one of the power boards 264V or 264C is connected to the contactorassembly 42 through four dedicated power flexible attachments 46P. Thedriver board 262 is connected to the contactor assembly 42 throughdedicated signal flexible attachments 46S. The flexible attachments 46have been described with reference to FIG. 3. The flexible attachments46 connecting at interface 92 at the distribution board 48 also providealternating current (AC) ground from the contactor assembly 42 to theboards 262 and 264.

The apparatus 10 further includes a ground plate 460 and a Bussedlow-voltage differential signaling (LVDS) backplane 462 mounted withinthe test head 20. The power boards 264V and 264C and the driver board262 each have two direct current (DC) connection pins 508, asillustrated in FIG. 18, that connect to the ground plate 460. The DCpins 508 also pass through the ground plate 460 and connect to theconnector block support piece 184, shown in FIG. 17. DC ground cables464 connect the connector block support piece 184 to the signaldistributor board 48, shown in FIG. 4, at the DC connection site 461,illustrated in FIG. 6, and thereby provide a DC ground path from theboards 262 and 264, the contactor assembly 42, and the wafer 76. FIG. 3illustrates connectors 466 to which the DC ground cables 464 areattached at the connector block support piece 184 of the cartridge 18.

The boards 260, 262, 264C, and 264V each have a connection that connectsa respective board to the Bussed LVDS backplane 462. A logical link isthereby provided between the boards 260, 262, 264C, and 264V, allowingthe boards to communicate with one another. It is also the Bussed LVDSbackplane 462 that provides the logical link between the boards 260,262, and 264 illustrated in FIG. 22.

The apparatus 10 further has a system control bay 470 that includes adie bulk power supply 472V for high voltage, a die bulk power supply472C for high current, the local controller 306 described with referenceto FIG. 22, and a system controller 474. The die bulk power supply 472Vcan provide a voltage of 0.5 V to 13 V at 110 A, and the die bulk powersupply 472C can provide a voltage of 0.5 V to 7 V at 200 A. The die bulkpower supply 472V is connected through respective power cables 476 topower board(s) 264V. Similarly, the die bulk power supply 472C isconnected through respective power cables 476 to power board(s) 264C.

An Ethernet link 478 connects and networks the die bulk power supplies472V and 472C, the local controller 306, the system controller 474, andthe boards 260, 262, 264C, and 264V with one another. The localcontroller 306 controls the boards 260, 262, 264C, 264V, and 474 throughthe Ethernet link 478 and peripheral components of the apparatus 10.

FIG. 28 illustrates one of the power boards 264V or 264C and itsconnections to the ground plate 460 and power flexible attachments 46P.A board-level control and bulk power control 490 is connected to theEthernet link 478. A board power control 492 and calibration control 494are connected to the board-level control and bulk power control 490. Theboard-level control and bulk power control 490, device power timingsystem 500, and the calibration control 494 are connected to a referenceand measurement system 496 and provide a series of instructions to thereference and measurement system 496. The instructions have beendescribed with reference to FIG. 22 (the instructions that are providedby the board-level control and bulk power control 490, the device powertiming system 500, and calibration control 494 to the reference andmeasurement system 496 have, for purposes of explanation, been equatedto chords in a music score).

The pattern generator board 260 has a pattern generator power timing busthat is connected through the Bussed LVDS backplane to a device powertiming system 500. The device power timing system 500 is connected tothe reference and measurement system 496. The device power timing system500 provides both timing and instructions to the reference andmeasurement system 496 for purposes of carrying out the instructionsthat are provided from the board-level control and bulk power control490 and calibration control 494 (the functioning of the device powertiming system 500 has, for purposes of explanation, been equated to anorchestra conductor that provides both timing and instructions of whichchords are to be played). The reference and measurement system 496includes eight logical systems of 64 channels each, thus totaling 512channels. Inputs into the reference and measurement system includesignals from the pattern generator index bus, pattern generator clocks,calibration reference, and ground sense. The reference and measurementsystem 496 performs voltage readback and current readback. Output fromthe reference and measurement system 496 includes four voltagereferences and device power control through a device power control bus.Output from the reference and measurement system 496 thus includes logicfor purposes of controlling power.

The reference and measurement system 496 and board-level control andbulk power control 490 are connected to a device power output system502. A positive side of the die bulk power supply 472V or 472C is alsoconnected to the device power output system 502 through power cable 476.The device power output system 502 regulates the power from the die bulkpower supply 472V or 472C, utilizing the signal from the reference andmeasurement system 496 (the power provided by the die bulk power supply472V or 472C has, for purposes of explanation, been equated to power orair that is provided simultaneously to a number of music instruments inan orchestra). The device power output system 502 includes 16 sectionsof 32 channels, grouped into 8 logical groups, thus totaling 512channels. Each channel includes a Kelvin sense system, each systemincluding one force (+F) and one sense (+S) line, so that there are atotal of 1,024 pins and circuits. Input into the device power outputsystem 502 includes references, bulk power, control parameters fromboard-level control and bulk power control 490, and device power controlthrough the device power control bus. The device power output system 502also provides voltage and current readback to the reference andmeasurement system 496 and channel status information to the board-levelcontrol and bulk power control 490.

Four of the power flexible attachments 46P are connected to the devicepower output system 502. Each power flexible attachment 46P includes 128+F lines, 128 +S lines, AC ground, and ground sense.

Two ground sense traces from each power flexible attachment 46P, thustotaling eight traces, are connected to a board ground control system506. The board ground control system 506 averages eight measurementsfrom the ground sense traces, and provides the averaged result as anoutput to the reference and measurement system 496.

A ground pin 508 is connected to the ground plate 460 and the firstconnector sets 44. The ground pin 508 is connected to both the devicepower output system 502 and to a board power system 510. The board powersystem 510 has a separate 48 V input, and can provide, for example,outputs of 15 V, 5 V, 3.3 V, −3.3 V, and 1.2 V. The DC ground cables 464are connected to the connector block support piece 184. The negativeside of the die bulk power supply 472V or 472C is also connected throughthe power cable 476 to the ground plate 460.

What should be noted is that separate paths are provided for AC groundand for DC ground. AC ground is provided through the flexibleattachments 46P that also deliver the power. The physical space betweenF+ power provision, the S+ line, and AC power ground in a power flexibleattachment 46P is extremely small, typically on the order of between0.002 and 0.010 inches. Such a small space allows for a substantialreduction in noise and an increase in speed, which is particularlyimportant for accurate measurement through the 512 sense lines and cleanpower delivery through the F+ lines. DC ground is provided through theDC ground cables 464. The AC and DC grounds have, for example,respective resistances of between 0.5 and 1.5 ohms and 0.003 and 0.015ohms.

FIG. 29 illustrates components of the device power output system 502 inmore detail. The device power output system 502 includes only a singleone of subsystem A. The subsystem B is replicated 512 times and is ineight groups of 64, and the 512 subsystems B are connected in parallelto the subsystem A. The subsystem C is replicated eight times, and theeight subsystems C are connected in parallel to the subsystem B.

Subsystem A includes die bulk power supply 472 and power cables 476which include an AC-to-DC conversion circuit comprising an inductor Iand a capacitor C1 connecting an output terminal of the inductor I toground and is controlled by board-level control and bulk power control490 and local controller 306 through Ethernet link 478. An inputterminal of the inductor I is connected to the die bulk power supply472V or 472C in FIG. 27. A stepped voltage cycle is provided to an inputterminal of the inductor I. An amplitude and a period of the steppedvoltage cycle always remain constant, but an amount of time that thevoltage is high during a particular period can be modulated. The totalamount of time that the voltage is high can thus be modulated from asmall percentage of the total time to a large percentage of the totaltime. The inductor I and capacitor C1 convert the voltage step to a DCvoltage. The DC voltage can thus also be modulated, depending on thepercentage of time that the voltage provided to the input terminal ofthe inductor I is high. The die bulk power supply 472V or 472C allowsfor a variable voltage to be created per power board 264. The DC voltagecan thus be modulated, depending on the need to control powerdissipation in the device power output system 502. The reference andmeasurement system 496 allows for 16 different voltages to be createdper group of 64 channels. Different voltages can be provided todifferent groups of 64 channels at a particular moment in time.

The DC voltage created by the subsystem B is provided through a force F+line through a power terminal 72P to a power contact 74P of a respectivedevice 300 (see also reference numerals 72 and 74 in FIG. 4). A senseline S+ is connected to the power terminal 72 or 56 and detects avoltage at the power terminal 72. The voltage detected by the sense lineS+ is provided through a resistor R2, an amplifier A3, and a resistor R1to control a MOSFET 1 located in the force line F+. The amplifier A3also receives at its positive terminal an input (Vref) through a switch594. The amplifier A3 is set so that the voltages provided at itspositive and negative terminals are combined to provide an outputvoltage to the MOSFET 1. The voltage Vrefout provides an input voltage,which is the desired voltage provided to the power terminal 72P, and thesense line S+ provides a feedback through the amplifier A3 to keep thevoltage provided to the MOSFET 1, and therefore the power terminal 72P,at a steady state. The amplifier A3 provides a voltage (Vrefout+V_(GS)),in this case 2.3 V, to the MOSFET 1 if the voltage provided by thesubsystem A is 1.5 V and the power terminal 72P requires a voltage of 1V. The MOSFET 1 dissipates heat equivalent to a difference between thevoltage provided by the subsystem A and the voltage on the force lineF+, multiplied by the current. For example, the voltage provided by thesubsystem A can be 1.5 V, and the force line F+ can provide a voltage of1 V. If the current is 1 A, the power dissipated by the MOSFET 1 is 0.5W. Should the voltage provided by the subsystem A always be a maximumof, for example, 12 V, the MOSFET 1 would have to dissipate 11 W. Thevariable power provided by the die bulk power supplies 472V and 472C inFIG. 27 thus substantially assists in reducing the amount of energy, andtherefore heat, dissipated by the MOSFET 1.

A resistor R3 is connected between the force and sense lines F+ and S+and resistively connects the F+ to the S+ of the amplifier A3. Theresistor R3 serves to control the amplifier A3 in case of a failure byholding the force and sense lines F+ and S+ to similar voltages. Theresistor R3 is thus just a safety device in case of contact failure.

The subsystem B also includes a circuit that automatically switchespower to the device 300 off upon the detection of an overcurrent, amongother things. The overcurrent detection and switching circuit includes aresistor R6 located after the MOSFET 1 in the force line F+. A voltageover the resistor R6 is linearly related to a current through the forceline F+. An amplifier A1 amplifies the voltage detected over theresistor R6. A comparitor A2 compares an output from the amplifier A1 toa current set point supplied by reference and measurement system 496. Anoutput from the comparitor A2 would be zero if the output from theamplifier A1 is the same as, or greater than, the current set point.

The output from the comparitor A2 provides an indication of anovercurrent or undercurrent through the resistor R6. The output from thecomparitor A2 is provided to a field programmable gate array (FPGA) 1.The FPGA 1 has logic that determines whether the over- or undercurrentis sufficient to switch subsystem B off. The FPGA 1 also provides for atiming delay before switching the current off, to allow for brief surgesin current without switching the current off. An output of the FPGA 1 isprovided to a switch 1 594 and a switch 2 594.

During normal operating conditions, i.e., when the current shouldcontinue to flow, the switch 1 is switched into its “off” position andthe switch 2 in its “A” position. A voltage of 15 V is provided througha resistor R5 to one terminal of the switch and to a MOSFET 2 locatedafter the resistor R6 in the force F+ line. During normal operatingconditions, the voltage provided through the resistor R5 maintains theMOSFET 2 in an “on” position, thereby allowing current to flow throughthe force line F+. Should an overcurrent be detected, the FPGA 1switches the switch 1 to its “on” position, thereby grounding thevoltage provided through the resistor R5, the MOSFET 2 will switch intoits “off” position and disconnect the current, and switch 2 is set tothe “B” position, shutting down the amplifier A3.

What should be noted is that each one of the 512 subsystems B has itsown overcurrent detection and switching circuit. The 512 overcurrent andswitching circuits allow for currents to one or more of the 512individual devices to be switched off, while current to the otherdevices continues to flow. Current measurement and voltage measurementcan also be done on a per-device level, because each one of thesubsystems B has a respective current measurement line (Imeas), and arespective voltage measurement line (Vmeas). The current measurementline Imeas is connected to an output of the amplifier A1, and thevoltage measurement line Vmeas is connected to the sense line S+. Thecurrent and voltage measurement lines Imeas and Vmeas allow forreal-time measurement of current and voltage provided to the powerterminal 72P. The subsystem B also includes a switching circuit having aresistor R4 and a MOSFET 3. The resistor R4 is connected to the forceline F+ after the MOSFET 2, and the MOSFET 3 is connected in seriesafter the resistor R4. A test signal (Test) can be provided to theMOSFET 3, thereby drawing current through the force line F+ forself-testing.

A high-frequency response is required for the circuit that includes theresistors R1, R2, and the amplifier A3. For this purpose, a capacitor C3is provided in parallel with the integrated circuit of the device 300.The capacitor C3 is built into the support structure 80 shown in FIG. 4.The force line F+ should have a relatively low inductance to allow forproper functioning of the capacitor C3 and high-frequency response ofthe circuit, including the resistors R1 and R2 and the amplifier A3. Forthis purpose, the force line F+ includes two sets of parallel powerconductors 590 and 592, respectively. The subsystems A and B areconnected to a single substrate with the conductors 590 of the first setbeing traces that are formed on the substrate. The conductors 590 allhave first ends that are connected to one another and second ends thatare connected to one another, so that middle sections of the conductors590 conduct current in parallel. The second ends of the conductors 590are connected to a common pin. The conductors 592 are in the form ofindividual electric lines in a respective power flexible attachment 46P.First ends of the conductors 592 are connected to one another and secondends of the conductors 592 are connected to one another, so that middlesections of the conductors 592 conduct the current received from theconductors 590 in parallel. The second ends of the conductors 592 areall connected to one power terminal 72P.

The distribution board 48 has two ground sense contacts at eachinterface 92. Ground sense terminals at each interface 92 connect to theground sense contacts 74G. Eight ground sense lines are provided to agrounding modulation circuit, including an amplifier A4 and a filter201. The voltage detected at the ground sense contact 74G is added bythe ground modulation circuit to a variable input voltage (Vrefin).Ideally, the voltage detected at the ground sense contact 74G is 0 V, inwhich case the voltage variable Vrefin would be equal to the voltageVrefout. If the voltage detected at the ground sense contact 74G is notzero, for example, it is 0.1 V, then Vrefout would be driven to 1.1 V(Vrefin+0.1 V). The voltage provided to the negative terminal of theamplifier A3 would then also be 1.1 V, and the voltage provided to thepower terminal 74P would be 1.1 V.

FIG. 30 illustrates one channel of the driver board 262 shown in FIGS.22 and 27. The same signal illustrated in FIG. 30 is replicated for eachof multiple channels of the driver board 262.

Also illustrated in FIG. 30 are multiple ones of the devices 300 andtheir respective ground sense contacts 72G. Voltages detected byrespective ground sense terminals on the ground sense contacts 74G (or72G) are averaged and provided to a filter 700. Under normal operatingconditions, the voltage provided to the filter 700 would be 0 V. Theremay sometimes be a small deviation from 0 V, for example, 0.1 V. The 0.1V is provided by the filter 700 to a positive terminal of an amplifierA4. A negative terminal of the amplifier A4 is then also driven to 0.1V. One resistor R9 is connected between the negative terminal and anoutput of the amplifier A4. A resistor R10, having the same resistanceas the resistor R9, is also connected to the negative terminal of theamplifier A4. A 10 V voltage source 702 is connected over the resistorsR9 and R10. Two terminals of the voltage source 702 are then 5 V aboveand 5 V below the voltage at the negative terminal of the amplifier A4,and thus at −4.9 V and 5.1 V, respectively.

The terminals of the 10 V voltage source 702 are connected to respectiveterminals R+ and R− of a digital-to-analog converter (DAC) 704. The DAC704 also has output terminals, and has the ability to switch each outputterminal to a voltage between −4.9 V and 5.1 V.

A microprocessor bus 705 is connected to the DAC 704. Informationrepresenting desired high and low voltages can be loaded from themicroprocessor bus 705 into the DAC 704. The DAC 704 can, for example,be programmed with a high voltage of 3 V and a low voltage of 2 V.Because the voltage provided to the positive terminal of the amplifierA4 is at 0.1 V, the output terminals of the DAC are, in this example,held at 3.1 V and 2.1 V, respectively.

The output terminals of the DAC are connected to high-voltage andlow-voltage (VH and VL) terminals of a voltage switch 706. The patterngenerator board 260 illustrated in FIGS. 22 and 27 provides a signalsource 708 to a signal terminal of the switch 706. The voltage switch isa bus switch in the present example, having a 5 V power supply voltage.The signal source 708 switches between alternating true and falsestates. In a true state, a first terminal of the switch 706 connected tothe high-voltage VH is connected to an output of the switch 706, and ina false state, the terminal connected to the low-voltage VL is connectedto the output of the switch 706. The output of the switch 706 thusswitches between 3.1 V and 2.1 V in response to the signal source 708.

A damping circuit, including a resistor R11 and a capacitor C4, has aninput connected to the output of the switch 706. The resistor R11 hasone terminal connected to the switch 706, and an opposing terminal ofthe resistor R11 is connected through the capacitor C4 to ground. Aneffect of the damping circuit represented by the resistor R11 andcapacitor C4 is that a slew rate of a signal provided on the output ofthe switch 706 is reduced. The switch 706 provides a square wave at itsoutput, and the damping circuit has an output that responds to thesquare wave in a non-square fashion. Specifically, the voltage on theoutput of the damping circuit increases more slowly than the voltageprovided to the input of the damping circuit.

The response voltage of the damping circuit is provided to an amplifierA5 with a gain of two, and then through a switch 708 to respectivesignal contacts 74S (see also reference numeral 74 in FIG. 4) of thedevices 300. Because the signal provided to the devices 300 is dampened,ringing can be reduced or be eliminated.

FIG. 31 illustrates a prior art solution, wherein a termination dampingcircuit is provided at a termination of one device. The terminationdamping circuit provides a dampening effect at the device that is beingtested. However, the functioning of the termination depends to a largeextent on the length of a line connected to the device that is beingtested. As illustrated in FIG. 30, the signal contacts 74S can be atdifferent distances from the damping circuit, as measured along a lengththat current flows in the circuit, and can be used without a terminationdamping circuit. Furthermore, the signal contacts 74S can be spaceddifferently from one application to another, for example, by 10 inchesin one application and 18 inches in another application, and the samedamping circuit will reduce ringing in each application.

FIG. 32 illustrates components of a cartridge 600, according to anotherembodiment of the invention, including a cartridge frame 602, a piston604, a piston adjustment system 606, first, second and thirdvolume-defining rings 608, 610, and 612, a stiffener substrate 614, adistribution board 616, a contactor board 618, and a stand-off layer620.

The cartridge frame 602 includes upper support pieces 622, a lowerbacking plate 624, and connecting pieces 626 that connect the lowerbacking plates 624 to the upper support pieces 622. The lower backingplate 624 defines a side portion 628 and a rear portion 630 of acylinder having an internal radius R1.

The piston 604 has an internal portion 632 and an external portion 634.The internal portion 632 has an outside radius R2 that is substantiallysmaller than the radius R1. The external portion 634 is mounted on alower side of the internal portion 632 and also has an outside radiusR1.

The first volume-defining ring 608 has an outer radius R1, which is thesame as the internal radius of the cylinder defined by the side portion628. The first and second volume-defining rings 608 and 610 have thesame internal and external radii R4 respectively and the second andthird volume-defining rings 610 and 612 have the same internal andexternal radii R5 respectively. The third volume-defining ring 612 hasan internal radius R2, which is the same as the external radius R2 ofthe internal portion 632 of the piston 604.

A fastener 638 is inserted from below through the first volume-definingring 608. Fasteners 640 and 642 are inserted from above into the secondand third volume-defining rings 610 and 612 respectively.

As shown in FIG. 33, the first volume-defining ring 608 is inserted intothe cylinder defined in the lower backing plate 624 and the fastener 638is used to secure the first volume-defining ring 608 to the rear portion630 of the cylinder. The lower backing plate 624 and the firstvolume-defining ring 608 thereby form a structural unit.

The third volume-defining ring 612 is positioned over the internalportion 632 and the second volume defining ring 610 is positioned overthe third volume-defining ring on an upper surface of the externalportion 634. The second and third volume-defining rings 610 and 612 arethen secured to the external portion 634 with the fasteners 640 and 642respectively. The third volume-defining ring 612 effectively increasesthe radius of the internal portion 632 of a main piston from the radiusR2 to the radius R5 and the second volume-defining ring 610 effectivelyincreases the radius from R5 to R4. The second and third volume-definingrings 610 and 612 thus increase the upper surface of the internalportion 632 of the piston 604 proportional to the square of the radius.

The stiffener substrate 614 is made of a metal and is thicker than thedistribution board 616, contactor board 618 and stand-off layer 620alone or in combination. The stiffener substrate 614 also has a largersurface area than the external portion 634 of the piston 604. Thestiffener substrate 614 is positioned against a lower surface of theexternal portion 634 of the piston 604 and fasteners 642 are used tosecure the stiffener substrate 614 to the piston 604.

The distribution board 616 and the contactor board are secured to oneanother and may be of the kind herein before described with reference toFIG. 4. A primary difference between the distribution board 616 and thedistribution board 48 in FIG. 4 is that the distribution board 48 ofFIG. 4 has an interface of contacts 58 on a lower surface thereof,whereas the distribution board 616 of FIG. 32 has an interface ofcontacts on an upper surface thereof.

The piston adjustment system 606 includes a spring 644 and a springadjustment mechanism formed by an elongate member 646 and a nut 648. Theelongate member 646 has a first end 650 and a second, opposing end 652.Both ends 650 and 652 are threaded. The first end 650 is insertedthrough an opening in the rear portion 630 of the cylinder so that thefirst end 650 is located within the cylinder and the second end 652 islocated outside the cylinder. The spring 644 is a coil spring that ispositioned over the elongate member 646. The nut 648 has an internalthread that is screwed onto the external thread of the second end 652 ofthe elongate member 646.

As shown in FIG. 34, the internal portion 632 and the second and thirdvolume-defining rings 610 and 612 are inserted into the cylinder and thefirst end 650 of the elongate member 646 is screwed into a threadedopening in the internal portion 632. The nut 648 is tightened so thatthe spring 644 compresses. The spring 644 is thus connected through thenut 648 and elongate member 646 to the piston 604.

FIG. 35 illustrates that three springs 644 are connected to the piston604. Although not shown in detail, each one of the springs 644 formspart of a respective piston adjustment system. The forces created by thesprings 644 are combined to overcome a gravitational force of the piston604 and all components that are eventually mounted to the piston 604 sothat the piston is initially seated against the rear portion 630 of thecylinder. When a pressure is applied on an upper surface of the piston604, the piston will move downward away from the rear portion 630 of thecylinder and the springs 644 will further compress. Certain areas of thepiston 604 may be heavier than other portions thereof so that the piston604 may have a tendency to droop in certain areas relative to thecylinder. The nuts holding respective ones of the springs 644 can beindependently tightened to level the piston 604 relative to thecylinder.

FIG. 35 further illustrates the positioning of three micrometers 653.The springs 644 are located at 0°, 120°, and 240° about a center pointof the piston 604. The micrometers 653 are located at 60°, 180°, and300° about a center point of the piston 604. Referring again to FIG. 34,bodies of the micrometers 653 are mounted on an upper surface of therear portion 630 defining the cylinder. Adjustable tips of themicrometers 653 extend through the rear portion 630 past a lower surfaceof the rear portion 630 into the cylinder. The tips are used asmechanical stops for the piston 604 when the piston 604 is retractedinto its uppermost position in the cylinder. The tips can be adjusted ina controlled manner to level the piston 604 and adjust the positioningof the piston 604 when it reaches its uppermost position in thecylinder. Precise positioning of the piston 604 is important, so that acamera forming part of the probing assembly 16 in FIG. 1 can find anaccurate reference position for the piston 604 when imaging thecontactor 618.

FIG. 36 shows a portion of the distribution board 616, contactor board618, stand-off layer 620, and a wafer 76. A contactor board assemblyjointly formed by the distribution board 616, contactor board 618 andthe stand-off layer 620 further includes a plurality of components 656that are mounted on and stand above an upper surface of the distributionboard 616. The components 656 may, for example, include resistors,capacitors, diodes, or other electrical components.

The stand-off layer 620 has an opening 658 formed therein and ispositioned on top of the distribution board 616 with the components 656in the opening 658. The stand-off layer 620 is not attached to an uppersurface of the distribution board 616 and can be removed from thedistribution board 616. Alternatively, a separate stand-off layer may belocated against and be attached to the distribution board 616.

As shown in FIG. 37, the stand-off layer 620 has a plurality of openings658 formed therethrough, and the electrical components 656 are locatedwithin each one of the openings 658. The openings 658 are primarilylocated in an array of rows and columns. A circuit layout of thecomponents 656 is in the form of an array that is repeated from oneopening 658 to the next.

The location of the components 656 on top of the distribution board 616saves space that would be taken up should the component 656, forexample, be mounted between the distribution board 616 and the contactorboard 618. The stand-off layer 620 forms a component through which aforce can be transferred from the stiffener substrate 614 in FIG. 34through an upper surface of the stand-off layer 620 to an upper surfaceof the distribution board 616 without damaging the components 656.

As shown in FIG. 38, the distribution board 616 is subsequently mountedto the stiffener substrate 614 with the stand-off layer 620 between thedistribution board 616 and the stiffener substrate 614. Fasteners 660are used to mount the distribution board 616 to the stiffener substrate614. The top portion of the cartridge 600 down to the stiffenersubstrate 614 form an assembly that will be common to all applications,although the components of the common subassembly may be connected toone another differently, depending on the application. The lower portionof the cartridge 600 from the stand-off layer 620 down to the contactor618 form a subassembly that will be uniquely designed depending onapplication. The uniquely designed portion of the cartridge 600 can beremoved by loosening the fasteners 660, and can be replaced with anotheruniquely designed subassembly, to again complete a cartridge such as thecartridge 600. The cartridge 600 is first removed from the apparatusframe to facilitate replacement of a first unique contactor subassemblywith a second unique contactor subassembly, whereafter a secondcartridge including the second unique contactor subassembly is againremovably mounted to the apparatus frame.

Sections of a vacuum passage 662 are formed through the rear portion 630of the cylinder, the piston 604, and the stiffener substrate 614. Anoutlet of the vacuum passage 662 is connected to a pump 664. When thepump 664 is switched on, a vacuum is created in a space between thepiston 604 and the stiffener substrate 614 and in cavities between thestiffener substrate 614 and the distribution board 616. Because of thevacuums that are created, the stiffener substrate 614 and the piston 604are pulled against one another and the distribution board 616 is pulledagainst the stiffener substrate 614. The stiffener substrate 614 ismanufactured so that lower surfaces thereof are planar to a tight degreeof tolerance. The distribution board 616 is a printed circuit board,which is typically manufactured to be planar to between 5 and 20 milsper inch. However, by pulling the distribution board 616 against thestiffener substrate 614 with the vacuum, the distribution board 616 hasa planarity that is less than 1 mil per inch.

As shown in FIG. 39, O-rings 666 are located between the volume-definingrings 608, 610, and 612 and between the volume-defining ring 608 and theside portion of the cylinder. A pressure and vacuum actuation passage668 is formed in the lower backing plate 624 and has first and secondends 670 and 672 as shown in FIG. 38. The first end 670 is located on alower surface of the lower backing plate 624 and the second end 672 islocated on an inner surface of the side portion 628 of the cylinder justbelow a lower surface of the first volume-defining ring 608. A fluidline (not shown) is connected to the second end 672.

FIG. 40 illustrates how the cylinder formed by the rear portion 630 andthe side portion 628, the volume-defining rings 608, 610, 612, and thepiston 604 form an actuator that moves the stiffener substrate 614relative to the cartridge frame 602. A pressure is applied through thepressure and vacuum actuation passage 668 to a space between a lowersurface of the first volume-defining ring 608 and a corresponding areaon an upper surface of the external portion 634 of the piston 604. Uppersurfaces of the internal portion 632 of the piston 604 and the secondand third volume-defining rings 610 and 612 remain only slightly belowambient pressure. A force is created with a magnitude equal to thepressure that is applied to the pressure and vacuum actuation passage668 and a surface area of the lower surface of the first volume-definingring 608. The force is used to move the piston 604 downward against aspring force of springs on the contactor board 618 and spring forces ofthe springs 644 in FIG. 35. The elongate member 646 and the nut 648 movedownward together with the piston 604 relative to the cartridge frame602, thereby compressing the spring 644 between the nut 648 and thelower backing plate 624. When the pressure and vacuum actuation passage668 returns to ambient pressure, the spring forces are not large enoughto return the piston 604 to the position shown in FIG. 38. When apressure below ambient pressure is applied to the pressure and vacuumactuation passage 668, the piston 604 moves from its position shown inFIG. 40 to its position shown in FIG. 38.

FIG. 41 shows how the force created by the piston 604 can be increasedwithout increasing the pressure within the pressure and vacuum actuationpassage 668. The piston 604 is removed from the lower backing plate 624as shown in FIG. 33. The second volume-defining ring 610 is removed byunscrewing the fastener 640 from the external portion 634 of the piston604. The second volume-defining ring 610 is then flipped over andinserted within the first volume-defining ring 608, where after thefastener 640 is screwed into the rear portion 630 of the cylinder. Thecartridge 600 is then reassembled as shown in FIG. 38, except that thesecond volume-defining ring 610 is secured to the lower backing plate624 and not the piston 604.

A pressure is applied through the pressure and vacuum actuation passage668 to an area below lower surfaces of the first and secondvolume-defining rings 608 and 610. An upper surface of the externalportion 634 having the same surface area as the combined surface areasof the lower surfaces of the first and second volume-defining rings 608and 610 is also exposed to the pressure applied through the pressure andvacuum actuation passage 668. Because a larger surface area of thepiston 604 is exposed to the pressure applied to the pressure and vacuumactuation passage 668 in FIG. 41 than in FIG. 39, the force applied bythe piston 604 is proportional to the pressure multiplied by the surfacearea that is exposed to the pressure, a larger force is created by thepiston in the configuration of FIG. 41 than in the configuration of FIG.39.

An even larger force can be created by the piston 604 by mounting thethird volume-defining ring 612 to the rear portion 630 of the cylinderinstead of the piston 604.

The O-rings 666 shown in FIG. 39 serve the purpose of isolating the highpressure below the lower surface of the first volume-defining ring 608from almost ambient pressure above upper surfaces of the second andthird volume-defining rings 610 and 612, while allowing for slidingmovement of the second volume-defining ring 610 relative to the firstvolume-defining ring 608. The O-rings 666, however, lead to staticfriction and therefore non-linear force created by the piston 604.

FIG. 42 illustrates an alternative embodiment wherein thevolume-defining rings 608, 610, and 612 of FIG. 39 are replaced with anactuator bladder 680. The actuator bladder 680 forms a toroidal ringaround the internal portion 632 of the piston 604 and is located betweenan upper surface of the external portion 634 of the piston 604 and alower surface of the rear portion 630. The pressure and vacuum actuationpassage 668 is connected to an internal volume 682 of the actuatorbladder 680. Upper and lower sides 684 and 686 of the actuator bladder680 move away from one another when the actuator bladder 680 is inflatedthrough the pressure and vacuum actuation passage 668, and move towardone another when air is removed from the internal volume 682 through thepressure and vacuum actuation passage 668. Movement of the sides 684 and686 away from one another causes downward movement of the piston 604.The pressure within the internal volume 682 can also create a force thatis counteracted by spring forces of springs in the contactor board 618and spring forces of the springs 644.

An advantage of the actuator bladder 680 is that no static friction iscreated and the force created by the actuator bladder 680 is thereforelinear. An advantage of the volume-defining rings 608, 610, and 612 isthat a cross-sectional surface area of the volume of an actuator normalto the direction of movement of the piston 604 relative to the cylinderdefined by the rear portion 630 and the side portion 628 can bemodified, and such modification will cause a corresponding modificationin force that is applied by the piston 604.

FIG. 43 illustrates the distribution board 616 in more detail. Thedistribution board 616 includes a plurality of horizontal layers 674G,674S, 674P, 676, 678A, and 678B located vertically on top of oneanother, and a plurality of vertical vias 679 extending through thelayers. The layers include metal layers in the form of ground layers674G, signal layers 674S, and power layers 674P, and the plurality ofinsulating layers including laminate layers 676 and coefficient ofthermal expansion (CTE) controlled layers 678A and 678B from a materialsuch as invar. A total of n (in this example, 36) metal layers 674G,674S, and 674P are included, which are alternated by a total of n−1 (inthis example, 35) insulating layers 676, 678A and 678B.

Each one of the metal layers 674G, 674S, and 674P, in isolation, hasabout the same stiffness as every other metal layer 674G, 674S, and674P. Each one of the laminate layers 676, in isolation, also hasapproximately the same stiffness. The CTE controlled layer 678A in thetop half of the distribution board 616, in isolation, has higherstiffness than any one of the metal layers 674G, 674S, 674P, or any oneof the laminate layers 676. The CTE controlled layer 678A also has alower CTE than any one of the laminate layers 676 or the metal layers674G, 674S, or 674P, so that the overall CTE of the distribution board616 is between that of the CTE controlled layer 678A and that of one ofthe laminate layers 676 or metal layers 674G, 674S, or 674P. The CTEcontrolled layers 678A and 678B combine to reduce the overall CTE of thedistribution board 616. The number or thicknesses of the CTE controlledlayers can be increased to further decrease the overall CTE of thedistribution board 616. The CTE controlled layer 678A and the CTEcontrolled layer 678B in the bottom half of the distribution board 616have approximately the same stiffnesses, each in isolation. The CTEcontrolled layers 678A and 678B provide the distribution board 616 withadditional stiffness, and therefore more planarity. The CTE controlledlayer 678A at the top is particularly useful for providing thedistribution boards 616 with additional stiffness and planarity, becauseit is located on the outside of the contactor board assembly formed bythe distribution board 616 and contactor board 618 shown in FIG. 33.

Each one of the horizontal layers 674P is a power layer that isseparately connected to one of the vias 679. Each one of the layers 674Gis a ground layer, and all the ground layers are connected to a commonvia 679. Current cannot conduct from one of the power vias 679 to one ofthe ground vias 679. A respective capacitor connects each one of thepower vias 679 to each one of the ground vias 679, and may be one of theelectric components 656 shown in FIG. 36. Each one of the metal layers674S is a signal layer. Two or more signal layers 674S are connected toeach one of the vias 679. The signal layers 674S are electricallydisconnected from both the power layers 674P and the ground layers 674G.

FIG. 44 illustrates a plurality of substantially identical contactorinterfaces 700 and a flexible attachment 702 connected to one of thecontactor interfaces 700. The contactor interface 700 is formed on anupper surface of the distribution board 616 in an area outside of thestiffener substrate 614. An opening 704 is formed in the lower backingplate 624. A first end of the flexible attachment 702 is insertedthrough the opening 704 so that the first end of the flexible attachment702 can reach the contactor interface 700. An opposite end of theflexible attachment 702 is connected to a connector array module such asthe first connector sets 44 in FIG. 17.

FIG. 45 shows components of the first end of the flexible attachment702, including a plurality of flexible cables 708, a plurality ofprinted circuit boards 710, a plurality of metal end pieces 712, a firstplurality of fasteners 714, a metal holding piece 716, a secondplurality of fasteners 718, a plurality of caps 720, a third pluralityof fasteners 722, and a fourth plurality of fasteners 724. FIG. 45 alsoshows a stiffener plate 726 having a plurality of threaded openings 728.

Each one of the flexible cables 708 is inserted through a respectiveopening 730 in the holding piece 716. Two of the flexible cables 708 aresecured to each one of the printed circuit boards 710. The fasteners 714secure two of the printed circuit boards 710 to each one of the metalend pieces 712. Three of the metal end pieces 712 are used to secure twoof the printed circuit boards 710 to one another. The fasteners 718 arethen used to secure each one of the metal end pieces 712 to the holdingpiece 716. Each one of the caps 720 is subsequently positioned over arespective one of the printed circuit board 710. A connector body isthereby formed by the holding piece 716, the metal end pieces 712,connected to substantially parallel connector body substrates of theprinted circuit boards 710, and the caps 720.

The fasteners 722 are used to secure the caps 720 to the metal endpieces 712. Each one of the caps 720 can be independently removed inorder to replace either the cap 720 that is being removed or the printedcircuit board 710 to which the cap 720 is secured. The fasteners 724 areused to secure the holding piece 716 to the distribution board 616 inFIG. 44.

A plurality of signal and ground conductors are held by the connectorbody. Each signal conductor includes one of a plurality of signal cores(not shown in FIG. 45), in each one of the flexible cables 708, arespective signal contact 732 on the substrate of one of the printedcircuit boards 710, a respective edge finger 734 on an edge of thesubstrate of the printed circuit board 710, and a respective contact 736on one of the caps 720.

As shown in FIGS. 46 and 47, each flexible cable 708 is a coaxial cablehaving a plurality of conductive signal cores 740, a plurality of groundconductors 742 that are coaxially located around the respectiveconductive signal cores, a plurality of separating insulating layers744, each separating a respective conductive signal core 740 from arespective ground conductor 742, and an outer insulating sheet 746.

Each ground conductor 742 protrudes from an end of the insulating sheet746. Each conductive signal core 740 protrudes from a respective one ofthe ground conductors 742. Each one of the conductive signal cores 740is independently soldered to a respective one of the signal contacts732. Each one of the ground conductors 742 is also soldered to a groundcontact 750 shown in FIG. 45. A solder bar 752 is used to connect theground conductors 742 electrically to one another so that the groundconductors 742 are at the same reference voltage. The solder bar 752extends to the fastener 722, which connects the solder bar 752electrically to one of the metal end pieces 712 in FIG. 45. Each one ofthe metal end pieces 712 is electrically connected to the holding piece716, so that the ground conductors 742 connected to all of the printedcircuit boards 710 are also electrically connected to the holding piece716. A large conductor is provided by the combined metal of all theground conductors 742. Although a large conductor is formed by theground conductors 742, the separation of the individual groundconductors 742 from one another allows for the flexible cables 708 toremain more flexible than if a single ground conductor is used havingthe same amount of metal as all the ground conductors 742 combined.

Traces are formed within each one of the printed circuit boards 710 thatconnect the ground contacts 750 to edge fingers 734 that are not usedfor signals. Ground can thus be provided through the flexible cable 708to the contacts 736 on the caps 720.

Referring again to FIG. 45, each one of the fasteners 724 has a shank753, a head 754, and thread 756. The thread 756 and the head 754 are onopposite sides of the shank 753. Two of the fasteners 722 also have pins760 extending therefrom, while other ones of the fasteners 722 do nothave any pins extending therefrom.

Referring to FIGS. 44 and 45 in combination, alignment openings 762 areformed in the distribution board 616. Each one of the pins 760 isaligned with and inserted into each one of the alignment openings 762.The locations of the pins 760 and the alignment openings 762 aresufficiently precise to ensure proper contact between surfaces ofcontacts 736 on the caps 720 and surfaces of terminals 764 on thecontactor interface 700. Openings 766 are also formed through thedistribution board 616, and the shanks 753 are inserted through theopenings 766 so that the heads 754 are on the front of the distributionboard 616. The thread 756 protrudes from the rear of the distributionboard 616 and engages with the threaded openings 728 of the stiffenerplate 726. The stiffener plate 726 provides a strong mount for theflexible attachment 702 without adding stresses to the distributionboard 616. The distribution board 616 is securely held or “sandwiched”between the stiffener plate 726 and the components of the flexibleattachment 702. The thread in the threaded opening 766 and the thread756 of the fasteners 724 are by themselves not manufactured to a highdegree of tolerance to ensure proper contact between the contacts 736 ofthe caps 720 and the terminal 764 of the contactor interface 700.

What should also be noted is that the alignment openings 762 arepositioned to ensure correct orientation of the connector subassembly ofthe flexible attachment 702. One of the alignment openings 762 at oneend of the connector interface 700 is located on a center line of theconnector interface 700. Another alignment opening 762 at an opposingend of the connector interface 700 is located off-center with respect toa center line of the connector interface 700. The alignment openings 762are thus not at the same locations on both ends of the connectorinterface 700. The locations of the alignment pins 760 are in the samelocations as the alignment pins 760. The alignment pins 760 will enterinto the alignment openings 762 if the connector subassembly of theflexible attachment 702 is aligned correctly, but will be misalignedwith respect to the alignment openings 762 if the connector subassemblyof the flexible attachment 702 is rotated through 180 degrees and willnot allow for connection between the connector interface 700 and thecontacts 736.

FIG. 48 shows that alignment pins 760 are located at opposing ends ofthe flexible attachment 702. The alignment pins 760 are arranged thesame at both ends of the flexible attachment 702 so that an operator canreverse the direction of the flexible attachment 702 while stillensuring proper connection. Identical connectors are thus provided atboth ends of the flexible cable 708.

FIG. 49 shows a cartridge 600A according to a further embodiment of theinvention. The cartridge 600A of FIG. 49 is similar to the cartridge 600of FIG. 32 and like reference numerals indicate like or similarcomponents. The cartridge 600A further includes a compensating piece 800that is located between the stiffener substrate 614 and the stand-offlayer 620. The standoff-layer 620 and the stiffener substrate are thusfirst and second pieces of a subassembly of the cartridge 600A.

The compensating piece 800 has an upper surface 802 that issubstantially flat and matches the substantially flat lower surface ofthe stiffener substrate 614. The compensating piece 800 has a lowersurface 804 that is not flat and has an undulating profile.

As shown in FIG. 50A, without the compensating piece 800, a lowersurface of the distribution board 616 and a lower surface 806 of thecontactor board 618 is not planar. Non-planarity of the lower surface ofthe distribution board 616 and the lower surface 806 of the contactorboard 618 is due to non-uniform thicknesses and due to compression ofthe stand-off layer 620 and the distribution board 616. FIG. 50B showsthe entire subassembly including the compensating piece 800. Thecompensating piece 800 compensates for the non-planarity of the lowersurface of the distribution board 616 and the lower surface 806 of thecontactor board 618 so that the lower surface 806 is substantiallyplanar. Specifically, the undulating lower surface 804 of thecompensating piece 800 is substantially a mirror reflection of the lowersurface 806 of the contactor board 618.

FIG. 50A illustrates only an edge, and therefore only a two-dimensionalprofile of the lower surface 806. As shown in FIG. 51, the lower surface806 has a three-dimensional profile, with a third dimension that extendsinto the paper in FIG. 50A. FIG. 52 illustrates a topography of thelower surface 804 of the compensating piece 800 in FIG. 50B. Thecompensating piece 800 consists of three shims 810, 812, and 814. Eachone of the shims 810, 812, and 814 is 75 microns thick. Thinner shimswill allow for more control. The shim 810 has a plurality of openings816 form therein to expose the lower surface of the stiffener substrate614 at an elevation of 0 microns. A lower surface of the shim 810 is atelevation of 75 microns below the lower surface of the stiffenersubstrate 614. The shims 812 and 814 are located on the lower surface ofthe shim 810 such that the shims 812 and 814 have lower surfaces at anelevation of 150 microns below the lower surface of the stiffenersubstrate 614.

FIG. 53 illustrates the distribution board 616, the contactor board 618,and a mounting arrangement 820 that is used to mount the contactor board618 to the distribution board 616. The mounting arrangement 820 includesa mounting ring 822, a plurality of fasteners 824 and 826, a supportarrangement 828, and an inner connecting arrangement 830.

The mounting ring fastener 826 secure the mounting ring 822 to thedistribution board 616. The support arrangement 828 includes a pluralityof flanges 832 and 834, and a plurality of flange fasteners 836. Theflange 832 is integrally manufactured with the mounting ring 822. Theflange fasteners 836 secure the flanges 834 to the mounting ring 822. Anedge of the contactor board 618 rests on upper surfaces of the flanges832 and 834.

The inner connecting arrangement 830 includes a first connecting piece838 forming part of the contactor board 618 and defining a slot 840 thatextends in a radial direction towards a center point of the contactorboard 618, a second connecting piece 842, and a plurality of connectingpiece fasteners 844. The second connecting piece 842 has a main portion846 and a finger 848 extending from the main portion 846. The fasteners844 secure the main portion 846 to the mounting ring 822. The finger 848extends in a radial direction towards a center point of the mountingring 822.

When the second connecting piece 842 is mounted to the mounting ring822, the slot 840 is aligned with the finger 848. The slot 840 is longerthan the finger 848 so that the finger 848 is permitted to sliderelatively within the slot 840 in a radial direction towards the centerpoint of the contactor board 618 and a center point of the mounting ring822. Inter-engagement of the finger 848 with the slot 840 preventstangential movement of the first connecting piece 838 relative to thesecond connecting piece 842, i.e. rotation of the contactor board 618relative to the distribution board 616 about a center point of thecontactor board 618 or a center point of the mounting ring 822. Relativemovement between the contactor board 618 and the mounting ring 822 isthus restricted to a line 850 extending in a radial direction through acenter point of the distribution board 618 and the mounting ring 822.

Referring to FIG. 54, four inner connecting arrangements 830 are locatedat 90° angles about a circumference of the mounting ring 822. Two of theconnecting arrangements 830 opposing one another restrict movement ofthe contactor board 618 relative to the distribution board 616 along theline 850. The other two connecting arrangements 830 restrict movementalong a line 852. The lines 850 and 852 are at right angles to oneanother and cross at a center point 854 of the contactor board 618 andthe mounting ring 822.

As previously mentioned, the materials of the contactor board 618 andthe distribution board 616 are engineered so that terminals and contactson the contactor board 618 and the distribution board 616 match oneanother at different temperatures. However, during a transition from onetemperature to another, it may happen that there is relative movementbetween corresponding contacts and terminals of the contact board 618and the distribution board 616 due to non-uniform expansion. Ifunchecked, non-uniform expansion can thus lead to misalignment betweencontacts and terminals. The connecting arrangements 830 ensure that acenter point (within a central area) of contactor board 618 is always ata center point of the mounting ring 822. The center points will thuscoincide with one another at a first temperature, during a transitionfrom the first temperature to a second temperature and at the secondtemperature. Because the center points coincide and because thematerials of the contactor board 618 and the distribution board 616 areengineered to ensure matching between contacts and terminals, thecontacts and terminals will match one another at the first temperatureand at the second temperature.

A shown in FIG. 55, two fastener openings 850 and 852 are formed througha portion of the mounting ring 822 and a plurality of grooves 854 areformed on an upper surface of the portion having the fastener openings850 and 852. Extensions of the grooves 854 cover a center point of themounting ring 822.

Referring to FIG. 56, a compliant piece 856 is located between theportion of the mounting ring 822 having the grooves 854 and thedistribution board 616. The compliant piece 856 is made of a compliantmaterial such as Kapton® so that a lower surface of the compliant piece856 acquires the shape of the grooves 854 when the compliant piece 856is sandwiched between the mounting ring 822 and the distribution board616. Relative movement of the portion of the mounting ring 822 havingthe grooves 854 and the complementary interengaging compliant piece 856is restricted to the direction in which the grooves 854 extend. Theportion of the mounting ring 822 with the grooves 854 and the compliantpiece 856 form one outer connecting arrangement.

Referring again to FIG. 54, eight fasteners 824 are located on themounting ring 822 at 45° intervals about the center point 854. Eachfastener 824 corresponds to the location of a respective compliant piecesuch as the compliant piece 856 in FIG. 56. The grooves 854 and thecompliant pieces 856 restrict movement of the mounting ring 822 so thatthe center point 854 of the mounting ring 822 is always at the samelocation relative to a corresponding location on the distribution board616 at any temperature or during a transition from one temperature toanother. The grooves 854 and the compliant pieces 856 thus furtherassist in maintaining contacts and terminals on the contactor board 618and the distribution board 616 in substantially the same locationsrelative to one another.

FIG. 57 shows that the fasteners 824 and 826 are bolts, each having ashank 860 and a head 862. The shank 860 of the fastener 824 has threadthat is screwed into complementary thread of the stiffener substrate614. The shank 860 of the fastener 826 has thread that is screwed into acomplementary thread of a nut 864 with the head 862 of the fastener 826located on an opposite side of the distribution board 616 than the nut864. The fastener 824 thus secures the distribution board 616 to thestiffener substrate 614 and the fastener 826 secures the mounting ring822 to the distribution board 616. What should further be noted is thatthe openings 850 and 852 are larger than the shanks 860 of the fasteners824 and 826. The shanks 860 can thus move relatively within the openings850 and 852 to allow for sliding movement of the mounting ring 822 onthe compliant piece 856. The fasteners 824 and 826, nuts 864, stiffenersubstrate 614, and the openings 850 and 852 all form part of the outerconnecting arrangements.

As further illustrated in FIG. 57, a pressure relief valve 870 isconnected to the pressure and vacuum actuation passage 668. The pressurerelief valve 870 includes a valve component 872 and a spring (notshown). The spring keeps the valve component 872 seated on a surface 874of the lower backing plate 628 as the pressure within the pressure andvacuum actuation passage 668 increases, the spring thus prevents openingof the valve component 872 to atmosphere. Once the pressure in thepressure and vacuum actuation passage 668 goes above a predeterminedpressure above atmosphere pressure, the pressure acts on a lower surfaceof the valve component 872 to overcome a spring force of the spring andmove the valve component 872 off the surface 874. Air within thepressure and vacuum actuation passage 668 then vents past the valvecomponent 872 to atmosphere. Air is thus automatically vented toatmosphere when the pressure within the pressure and vacuum actuationpassage 668 goes above the predetermined value.

Air continues to vent to atmosphere as long as the pressure within thepressure and vacuum actuation passage 668 is above the predeterminedpressure. When the pressure within the pressure and vacuum actuationpassage 668 again drops below the predetermined pressure, the springforce of the spring overcomes a force created by the pressure on thelower surface of the valve component 872 so that the valve component 872moves down and seats on the surface 874.

Venting of air to atmosphere is thus automatically terminated when thepressure within the pressure and vacuum actuation passage 668 fallsbelow the predetermined pressure. It can thus be seen that the valve 870prevents a pressure behind the piston 604 from becoming too large andthereby prevents damage to the cartridge 600A and to the wafer.

An orifice 876 is located within the pressure and vacuum actuationpassage 668. The size of the orifice 876, and therefore its resistanceto airflow, is chosen so that the valve 870 has a bleeding capacity thatis more than a capacity for air flowing through the orifice 876. Assuch, the mass of air within the pressure and vacuum actuation passage668 will not increase if the valve 870 is open. The orifice 876 therebyfurther prevents damage to the cartridge 600A and to the wafer.

FIG. 58 shows a pneumatic system 880 that is used for controlling thepiston 604 in FIG. 49. The pneumatic system 880 includes a high pressureline, a low pressure line, and a vacuum line. The high pressure line andthe low pressure line carry fluid in the form of air at pressures aboveatmospheric pressure, and the vacuum line carries air at a pressurebelow atmospheric pressure. The pneumatic system 880 further includes anactuation line 882 connected to the volume behind the piston 604.

The high pressure line includes a line connected to a high pressure pump884, and an air regulator 886. Air at high pressure is provided from thepump 884 to the air regulator 886. The air regulator 886 reduces thepressure of the air and provides the air at reduced pressure to the lowpressure line. The low pressure line includes a proportional controller888, a probe piston 890, an air tank 892, an isolation valve 894, and aprobe piston 896 located in series after one another. The vacuum lineincludes a line connected to a vacuum pump 898, the probe piston 896, acartridge clamp 900, and to the signal distribution board vacuum area902 as hereinbefore described. The low pressure line and the vacuum lineare thus both connected to the probe piston 896. The probe piston 896can be operated to selectively provide air from either the low pressureline or from the vacuum line to the activation line 882 connected to thepiston 604. The pneumatic system 880 also includes a vent valve 904 thatis connected to the low pressure line between the proportionalcontroller 888 and the probe piston 890, and an air pressure sensor 906that is connected to the high pressure line.

It will be understood that many of the components of the pneumaticsystem 880 are under the control of a computer or provide a controlinput into the computer. Such a computer has a processor and memoryconnected to the processor. A program having a series of instructions isstored in the memory and is executable by the processor. The airpressure sensor 906 is one component that provides a control input intothe computer for purposes of controlling other components of thepneumatic system 880. Specific components of the pneumatic system 880that are controlled by the computer include the vent valve 904, theisolation valve 894, the probe piston 896, the probe piston 890, and theproportional controller 888. The computer for example controls thepiston 896 to provide either air from the low pressure line or vacuumpressure to the piston 604. The computer also controls the isolationvalve 894 to isolate a volume behind the piston 604 from the highpressure pump 884 and the vacuum pump 898.

FIG. 59 illustrates how the pneumatic system 880 of FIG. 58 is used tocontrol movement and a force created by the piston 604 in FIG. 49. AtTime T0 the piston 604 is fully retracted into the lower backing plate624 in FIG. 49 so that the volume behind the piston 604 is at a minimumand the pressure behind the piston 604 is at negative or zero relativeto atmospheric pressure. The isolation valve 894 in FIG. 58 is open sothat the volume behind the piston 604 is not isolated. The wafer chuck130 of FIG. 8 is moved into an upward z-direction so that the terminals72 can come down and engage with the contacts on the wafer 76.

Between Time T0 and Time T1, the volume behind the piston 604 isincreased by operating the probe piston 896 in FIG. 58 such that airfrom the pressure line 882 is provided to the piston 604. There is onlya slight increase in the pressure behind the piston 604 to overcome theforce of the spring 644 in FIG. 49. At Time T1, the wafer chuck 130 isengaged, i.e. the contacts on the wafer 76 make contact with theterminals 72 in FIG. 8.

Between Times T1 and T2, the probe piston 896 in FIG. 58 remains open sothat the pressure behind the piston 604 increases. There is only aslight increase in the volume behind the piston 604 as the terminals 72compress. At Time T2, the forces created by the terminals 72 aresufficient to initiate testing. Testing is carried out for an intervalbetween Time T2 and T3.

Between Times T3 and T4 the pressure behind the piston 604 is reduced tozero. The volume only decreases slightly as the terminals 72 againexpand. The wafer chuck 130 remains engaged. At Time T5, the isolationvalve 894 is closed. The volume behind the piston 604 is thus isolated.When the volume behind the piston 604 is isolated, no air can flow intoor out of the volume behind the piston 604. It is also not possible toincrease or decrease the pressure of the air in the volume behind thepiston 604.

At Time T6, the wafer chuck 130 in FIG. 8 is moved vertically downwardinto a disengaged position wherein the terminals 72 do not make contactwith the contacts on the wafer 76. Because the isolation valve 894 inFIG. 58 is closed, and the volume behind piston 604 is isolated, thepiston 604 remains in a stationary position relative to the lowerbacking plate 624. Between Times T6 and T7, the wafer 76 on the waferchuck 130 is replaced with another wafer and the wafer chuck 130 isagain moved into the engaged position. Contacts on the new wafer are nowin contact with the terminals 72. By maintaining the piston 604 in az-position, more consistent planarity in x- and y-directions can bemaintained from one wafer to the next.

At Time T8, the isolation valve 894 in FIG. 58 is again opened. BetweenTimes T9 and T10, the pressure is again increased and the volumeincreases only slightly as the terminals 72 compress. The sequence ofevents at Times T10, T11, T12, T13 and T14 are the same as the sequenceof events at Times T2, T3, T4, T5, and T6 respectively. The sequence ofevents can be repeated any number of times to test three wafers or more.

At Time T14, following testing a number of the wafers, the pressure isreduced to below atmospheric pressure. Negative pressure causes thepiston 604 to retract in a vertical z-direction into the lower backingplate 624 of FIG. 49.

The features of the cartridge 600A in FIGS. 49 to 59 may findapplication in a system having an actuator other than a piston such asthe piston 604. For example, features of cartridge 600A may findapplication in conjunction with an activator in the form of a bladder ashereinbefore described.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative and not restrictive of the current invention, andthat this invention is not restricted to the specific constructions andarrangements shown and described since modifications may occur to thoseordinarily skilled in the art.

1. An apparatus for testing an integrated circuit of a device,comprising: an apparatus frame; a holder for the device, secured to theapparatus frame; a subassembly including: (i) a contactor supportstructure held by the apparatus frame; (ii) a compensating piece with athree-dimensional profiled surface that improves planarity of athree-dimensional profile of a surface of the subassembly other than theprofiled surface of the compensating piece; and (iii) a plurality ofterminals held by the contactor support structure, the holder andcontactor support structure being movable relative to one another sothat each one of the terminals releasably makes contact with arespective contact of the device; a power source; a power electricalpath connecting the power source to a power terminal of the terminalsheld by the support structure; a signal source; and a plurality ofsignal electrical paths, each connecting the signal source to arespective signal terminal of the terminals held by the supportstructure.
 2. The apparatus of claim 1, wherein the three-dimensionalprofile of the compensating piece makes the three-dimensional profile ofthe surface of the subassembly substantially planar.
 3. The apparatus ofclaim 1, further comprising: an actuator connected between the apparatusframe and the contactor support structure, having first and secondportions that are movable relative to one another to move the contactorsupport structure relative to the apparatus frame and toward the surfaceof the holder so that the terminals are urged against contacts of thedevice.
 4. The apparatus of claim 3, wherein the actuator has a volumedefined between the first and second components and a fluid lineconnected to the volume to allow air through the volume and therebymodify a size of the volume and move the contactor support structurerelative to the apparatus frame.
 5. The apparatus of claim 1, furthercomprising: a plurality of electrical components mounted on thecontactor support structure.
 6. The apparatus of claim 5, wherein theelectrical components are mounted on a side on the contactor supportstructure opposing the terminals held by the contactor supportstructure.
 7. The apparatus of claim 5, further comprising: a forcedistribution substrate, the electrical components being located betweenthe force distribution substrate and the contactor support structure;and a stand-off component between the force distribution substrate andthe contactor substrate to transfer force from the contactor substrateto the force distribution substrate, the stand-off component beinglocated between the compensating piece and the surface of thesubassembly.
 8. The apparatus of claim 1, further comprising a contactorboard assembly having the contactor support structure, the terminals anda compensating piece with a profiled surface that improves planarity ofa surface of the contactor board assembly other than the profiledsurface of the compensating piece.
 9. The apparatus of claim 1, whereinthe contactor support structure includes a distribution board substrateand a contactor substrate mounted to the distribution board substrate.10. The apparatus of claim 1, further comprising: cartridge including acartridge frame that is removably mountable to the apparatus frame, acontactor board forming part of the cartridge; a contactor interface onthe contactor support structure; and a connector interface having asurface for connecting to a surface of the contactor interface.
 11. Theapparatus of claim 10, wherein the cartridge includes a commonsubassembly and a first unique contactor subassembly that is replaceablewith a second unique contactor subassembly.
 12. The apparatus of claim11, further comprising: a pressure reduction passage in communicationwith an area between the common subassembly and the second uniquecontactor subassembly and having an outlet on an external side of thecartridge; and a pump connected to the outlet of the pressure reductionpassage so as to reduce a pressure in the area between the commonsubassembly and the second unique contactor subassembly, thecompensating piece compensating for at least a profile change of thesurface due to said reduction in pressure.
 13. A cartridge, comprising:a cartridge frame; formations on the cartridge frame for mounting thecartridge frame in a fixed position to an apparatus frame; a subassemblyincluding: (iii) a contactor support structure held by the apparatusframe; (iv) a compensating piece with a three-dimensional profiledsurface that improves planarity of three-dimensional profile of asurface of the subassembly other than the profiled surface of thecompensating piece; (v) a plurality of terminals held by the contactorsupport structure, the holder and contactor support structure beingmovable relative to one another so that each one of the terminalsreleasably makes contact with a respective contact of the device; and acontactor interface on the contactor support structure; and a pluralityof conductors, held by the contactor support structure, connecting theinterface to the terminals.
 14. The cartridge of claim 13, wherein thethree-dimensional profile of the compensating piece makes thethree-dimensional profile of the surface of the subassemblysubstantially planar.